Development of the infant intestine: implications for nutrition support

Exclusive enteral nutrition in preterm infants: How early is too early?

With the growing availability of maternal and donor milk, neonatal feeding practices are undergoing significant transformation. Increasingly, neonatal units are prioritizing exclusive enteral nutrition soon after birth, a shift that represents a substantial advance in neonatal care. However, critical questions remain regarding the implementation, safety, and long-term outcomes of this approach. This review consolidates the evidence supporting early and exclusive enteral nutrition, exploring its potential to redefine neonatal care practices, particularly in high-resource settings. By examining challenges such as variability in practices, resource constraints, and clinical decision-making during acute illness, this discussion aims to provide a roadmap for integrating these practices into routine care and advancing outcomes for preterm and vulnerable infants.

The Practice of Enteral Nutrition: Clinical Evidence for Feeding Protocols

Establishing full enteral nutrition in critically ill preterm infants with immature gastrointestinal function is challenging. In this article, we will summarize emerging clinical evidence from randomized clinical trials suggesting the feasibility and efficacy of feeding interventions targeting the early establishment of full enteral nutrition. We will also examine trial outcomes of higher volume feedings after the establishment of full enteral nutrition. Only data from randomized clinical trials will be discussed extensively. Future opportunities for clinical research will also be presented.

Maternal Epidermal Growth Factor Promotes Neonatal Claudin-2 Dependent Increases in Small Intestinal Calcium Permeability

A higher concentration of calcium in breast milk than blood favors paracellular calcium absorption enabling growth during postnatal development. We aimed to determine whether suckling animals have greater intestinal calcium permeability to maximize absorption and to identify the underlying molecular mechanism. We examined intestinal claudin expression at different ages in mice and in human intestinal epithelial (Caco-2) cells in response to hormones or human milk. We also measured intestinal calcium permeability in wildtype, Cldn2 and Cldn12 KO mice and Caco-2 cells in response to hormones or human milk. Bone mineralization in mice was assessed by μCT. Calcium permeability across the jejunum and ileum of mice were 2-fold greater at 2 wk than 2 mo postnatal age. At 2 wk, Cldn2 and Cldn12 expression were greater, but only Cldn2 KO mice had decreased calcium permeability compared to wildtype. This translated to decreased bone volume, cross-sectional thickness, and tissue mineral density of femurs. Weaning from breast milk led to a 50% decrease in Cldn2 expression in the jejunum and ileum. Epidermal growth factor (EGF) in breast milk specifically increased only CLDN2 expression and calcium permeability in Caco-2 cells. These data support intestinal permeability to calcium, conferred by claudin-2, being greater in suckling mice and being driven by EGF in breast milk. Loss of the CLDN2 pathway leads to suboptimal bone mineralization at 2 wk of life. Overall, EGF-mediated control of intestinal claudin-2 expression contributes to maximal intestinal calcium absorption in suckling animals.

Early development of infant gut microbiota in relation to breastfeeding and human milk oligosaccharides

Background

Infant gut microbiota composition is influenced by various factors early in life. Here, we investigate associations between infant gut microbiome development, infant age, breastfeeding duration, and human milk oligosaccharides (HMO) composition in breastmilk.

Methods

A total of 94 mother-infant pairs were recruited as part of the Cambridge Baby Growth and Breastfeeding Study (CBGS-BF) (Cambridge, UK). Infant stool samples (n = 337) were collected at 2 week, 6 week, 3 month, and 6 month of age. The 16S rRNA V3-V4 rRNA region was sequenced using MiSeq Illumina to determine microbiota composition and diversity. Mother's hindmilk samples were collected at birth, 2 week, 6 week, 3 month, and 6 month postpartum. Concentrations of five neutral [2'FL, 3'FL, lacto-N-fucopentaose 1 (LNFP1), LNnT, LNT] and two acidic (3'SL, and 6'SL) HMOs were measured in all milk samples using High-Performance Anion-Exchange Chromatography with Pulsed Amperometric Detection (HPAEC-PAD). We explored the associations between infant gut microbiome parameters and age, duration of exclusive breastfeeding (EBF), and levels of individual HMOs.

Results

Bifidobacterium was the most abundant genus in infant stool at all-time points, irrespective of breastfeeding duration, with an overall mean relative abundance of 70%. The relative abundance of B. bifidum in stool from infants who were breastfed for longer than 6 months was significantly higher compared to the infant breastfed up to 3 months (p = 0.0285). Alpha-diversity (both Shannon and ASV-level Richness) of infant gut microbiota showed a biphasic change with infant age, decreasing from 2 weeks until 3 months and then increasing until 6 months of age. Bifidobacterium relative abundance was associated with higher concentrations of 2'FL and LNFP1 in breastmilk across all time-points (p = 0.049 and 0.017, respectively), with trends toward a higher abundance of B. longum species. No significant association with Bifidobacterium was found for breastmilk LNnT, 3'SL, and 6'SL levels.

Conclusion

Our study is in line with previous data demonstrating that EBF duration in the first months of life impacts infant gut microbiota composition. The observed links between specific HMOs in breastmilk and bacteria in infant stool provide evidence of how mother's milk affects infant microbiome development.

Short-term feeding of defatted bovine colostrum mitigates inflammation in the gut via changes in metabolites and microbiota in a chicken animal model

BACKGROUND

Nondrug supplement strategies to improve gut health have largely focused on the effects of individual compounds to improve one aspect of gut homeostasis. However, there is no comprehensive assessment of the reproducible effects of oral, short-term, low-level colostrum supplementation on gut inflammation status that are specific to the ileum. Herein, a chicken animal model highly responsive to even mild gut inflammatory stimuli was employed to compare the outcomes of feeding a standard diet (CON) to those of CON supplemented with a centrifuge-defatted bovine colostrum (BC) or a nonfat dried milk (NFDM) control on the efficiency of nutrient use, ileal morphology, gut nitro-oxidative inflammation status, metabolites, and the composition of the microbiota.

RESULTS

A repeated design, iterative multiple regression model was developed to analyze how BC affected ileal digesta-associated anti-inflammatory metabolite abundance coincident with observed changes in the ileal microbiome, mitigation of epithelial inflammation, and ileal surface morphology. An improved whole body nutrient use efficiency in the BC group (v CON and NFDM) coincided with the observed increased ileum absorptive surface and reduced epithelial cell content of tyrosine-nitrated protein (NT, biomarker of nitro-oxidative inflammatory stress). Metabolome analysis revealed that anti-inflammatory metabolites were significantly greater in abundance in BC-fed animals. BC also had a beneficial BC impact on microbiota, particularly in promoting the presence of the bacterial types associated with eubiosis and the segmented filamentous bacteria, Candidatus Arthromitus.

CONCLUSION

The data suggest that an anti-inflammatory environment in the ileum was more evident in BC than in the other feeding groups and associated with an increased content of statistically definable groups of anti-inflammatory metabolites that appear to functionally link the observed interactions between the host's improved gut health with an observed increase in whole body nutrient use efficiency, beneficial changes in the microbiome and immunometabolism.

Development of the Gastrointestinal Tract in Newborns as a Challenge for an Appropriate Nutrition: A Narrative Review

The second and third trimesters of pregnancy are crucial for the anatomical and functional development of the gastrointestinal (GI) tract. If premature birth occurs, the immaturity of the digestive and absorptive processes and of GI motility represent a critical challenge to meet adequate nutritional needs, leading to poor extrauterine growth and to other critical complications. Knowledge of the main developmental stages of the processes involved in the digestion and absorption of proteins, carbohydrates, and lipids, as well as of the maturational phases underlying the development of GI motility, may aid clinicians to optimize the nutritional management of preterm infants. The immaturity of these GI systems and functions may negatively influence the patterns of gut colonization, predisposing to an abnormal microbiome. This, in turn, further contributes to alter the functional, immune, and neural development of the GI tract and, especially in preterm infants, has been associated with an increased risk of severe GI complications, such as necrotizing enterocolitis. Deeper understanding of the physiological colonization patterns in term and preterm infants may support the promotion of these patterns and the avoidance of microbial perturbations associated with the development of several diseases throughout life. This review aims to provide a global overview on the maturational features of the main GI functions and on their implications following preterm birth. We will particularly focus on the developmental differences in intestinal digestion and absorption functionality, motility, gut–brain axis interaction, and microbiomes.

Review of paediatric gastrointestinal physiology relevant to the absorption of orally administered medicines

Despite much progress in regulations to improve paediatric drug development, there remains a significant need to develop better medications for children. For the design of oral dosage forms, a detailed understanding of the specific gastrointestinal (GI) conditions in children of different age categories and how they differ from GI conditions in adults is essential. Several review articles have been published addressing the ontogeny of GI characteristics, including luminal conditions in the GI tract of children. However, the data reported in most of these reviews are of limited quality because (1) information was cited from very old publications and sometimes low quality sources, (2) data gaps in the original data were filled with textbook knowledge, (3) data obtained on healthy and sick children were mixed, (4) average data obtained on groups of patients were mixed with data obtained on individual patients, and (5) results obtained using investigative techniques that may have altered the outcome of the respective studies were considered. Consequently, many of these reviews draw conclusions that may be incorrect. The aim of the present review was to provide a comprehensive and updated overview of the available original data on the ontogeny of GI luminal conditions relevant to oral drug absorption in the paediatric population. To this end, the PubMed and Web of Science metadatabases were searched for appropriate studies that examined age-related conditions in the oral cavity, esophagus, stomach, small intestine, and colon. Maturation was observed for several GI parameters, and corresponding data sets were identified for each paediatric age group. However, it also became clear that the ontogeny of several GI traits in the paediatric population is not yet known. The review article provides a robust and valuable data set for the development of paediatric in vitro and in silico biopharmaceutical tools to support the development of age-appropriate dosage forms. In addition, it provides important information on existing data gaps and should provide impetus for further systematic and well-designed in vivo studies on GI physiology in children of specific age groups in order to close existing knowledge gaps and to sustainably improve oral drug therapy in children.

Dynamic Associations of Milk Components With the Infant Gut Microbiome and Fecal Metabolites in a Mother-Infant Model by Microbiome, NMR Metabolomic, and Time-Series Clustering Analyses

Background: The gut microbiome and fecal metabolites of breastfed infants changes during lactation, and are influenced by breast milk components. This study aimed to investigate dynamic associations of milk components with the infant gut microbiome and fecal metabolites throughout the lactation period in a mother–infant model.

Methods: One month after delivery, breast milk and subsequent infant feces were collected in a pair for 5 months from a mother and an exclusively breastfed infant. Composition of the fecal microbiome was determined with 16S rRNA sequencing. Low-molecular-weight metabolites, including human milk oligosaccharides (HMOs), and antibacterial proteins were measured in feces and milk using ¹H NMR metabolomics and enzyme-linked immunosorbent assays. The association of milk bioactive components with the infant gut microbiome and fecal metabolites was determined with Python clustering and correlation analyses.

Results: The HMOs in milk did not fluctuate throughout the lactation period. However, they began to disappear in infant feces at the beginning of month 4. Notably, at this time-point, a bifidobacterium species switching (from B. breve to B. longum subsp. infantis) occurred, accompanied by fluctuations in several metabolites including acetate and butyrate in infant feces.

Conclusions: Milk bioactive components, such as HMOs, might play different roles in the exclusively breastfed infants depending on the lactation period.

Transcriptome analysis revealed that delaying first colostrum feeding postponed ileum immune system development of neonatal calves

Our objective was to evaluate the effect of colostrum feeding times on genome-wide gene expression of neonatal calves. In total, twenty-seven calves were assigned to three colostrum feeding treatments: within 45 min (TRT0h, n = 9), 6 h (TRT6h, n = 9) and 12 h (TRT12h, n = 9). Ileum tissues were collected at 51 h and transcriptomic analysis was conducted. Uniquely expressed genes were identified in TRT0h group with enriched "Antigen Presentation" function. Meanwhile, the weighted gene co-expression network analysis (WGCNA) identified four significant gene modules (|correlation| > 0.50 and P ≤ 0.05). In particular, Turquoise gene module with the enriched "Cadherin binding involved in cell-cell adhesion" and "Cell-cell adherences junction" GO terms were significantly correlated with Faecalibacterium prausnitzii (R = -0.70, P < 0.01) and Bifidobacterium (R = -0.55, P < 0.01). Our findings suggest feeding colostrum without delay could stimulate the expression of genes involved in immune function development related to host response and microbial colonization in neonatal claves.

From Mum to Bum: An Observational Study Protocol to Follow Digestion of Human Milk Oligosaccharides and Glycoproteins from Mother to Preterm Infant

The nutritional requirements of preterm infants are challenging to meet in neonatal care, yet crucial for their growth, development and health. Aberrant maturation of the gastrointestinal tract and the microbiota could affect the digestion of human milk and its nutritional value considerably. Therefore, the main objective of the proposed research is to investigate how the intestinal microbiota of preterm and full-term infants differ in their ability to extract energy and nutrients from oligosaccharides and glycoproteins in human milk. This pilot study will be an observational, single-center study performed at the Neonatal Intensive Care Unit at Isala Women and Children's Hospital (Zwolle, The Netherlands). A cohort of thirty mother-infant pairs (preterm ≤30 weeks of gestation, n = 15; full-term 37-42 weeks of gestation, n = 15) will be followed during the first six postnatal weeks with follow-up at three- and six-months postnatal age. We will collect human milk of all mothers, gastric aspirates of preterm infants and fecal samples of all infants. A combination of 16S rRNA amplicon sequencing, proteomics, peptidomics, carbohydrate analysis and calorimetric measurements will be performed. The role of the microbiota in infant growth and development is often overlooked yet offers opportunities to advance neonatal care. The 'From Mum to Bum' study is the first study in which the effect of a preterm gut microbiota composition on its metabolic capacity and subsequent infant growth and development is investigated. By collecting human milk of all mothers, gastric aspirates of preterm infants and fecal samples of all infants at each timepoint, we can follow digestion of human milk from the breast of the mother throughout the gastrointestinal tract of the infant, or 'From Mum to Bum'.

Maturation of the preterm gastrointestinal tract can be defined by host and microbial markers for digestion and barrier defense

Functionality of the gastrointestinal tract is essential for growth and development of newborns. Preterm infants have an immature gastrointestinal tract, which is a major challenge in neonatal care. This study aims to improve the understanding of gastrointestinal functionality and maturation during the early life of preterm infants by means of gastrointestinal enzyme activity assays and metaproteomics. In this single-center, observational study, preterm infants born between 24 and 33 weeks (n = 40) and term infants born between 37 and 42 weeks (n = 3), who were admitted to Isala (Zwolle, the Netherlands), were studied. Enzyme activity analyses identified active proteases in gastric aspirates of preterm infants. Metaproteomics revealed human milk, digestive and immunological proteins in gastric aspirates of preterm infants and feces of preterm and term infants. The fecal proteome of preterm infants was deprived of gastrointestinal barrier-related proteins during the first six postnatal weeks compared to term infants. In preterm infants, bacterial oxidative stress proteins were increased compared to term infants and higher birth weight correlated to higher relative abundance of bifidobacterial proteins in postnatal week 3 to 6. Our findings indicate that gastrointestinal and beneficial microbial proteins involved in gastrointestinal maturity are associated with gestational and postnatal age.

Effect of Oropharyngeal Administration of Mother's Milk Prior to Gavage Feeding on Gastrin, Motilin, Secretin, and Cholecystokinin Hormones in Preterm Infants: A Pilot Crossover Study

BACKGROUND

Oropharyngeal administration of milk prior to gavage feeding has been shown to improve feeding tolerance in preterm infants.

OBJECTIVES

The aim is to study the effect of oropharyngeal administration of mother's milk (OPAMM), prior to gavage feeding, on the levels of gastrin, motilin, secretin, and cholecystokinin hormones.

METHODS

Preterm infants (<32 weeks' gestation) were randomized at a corrected gestational age of 33-34 weeks, in a crossover design, to receive 1 of 2 protocols: 24 hours of OPAMM practice (applying 0.2 mL of mother's milk prior to each gavage feeding) followed by 24 hours of regular gavage-feeding practice in the first protocol or vice versa in the second protocol. The levels of gastrin, motilin, secretin, and cholecystokinin hormones were measured at the end of 24 hours of both practices.

RESULTS

The data of 40 preterm infants (20 in each protocol) were analyzed. OPAMM was associated with a significant increase in the levels of motilin (median, 233; interquartile range [IQR], 196-296 vs median, 196; IQR, 128-233; P < .01), secretin (median, 401; IQR, 353-458 vs median, 370; IQR, 331-407; P = .04), and cholecystokinin (median, 21.4; IQR, 16-27.1 vs median, 14.9; IQR, 11-20.5; P <.01) but not gastrin (median, 202; IQR, 125-238 vs median, 175; IQR, 128-227; P = .7), compared with regular gavage-feeding practice.

CONCLUSION

Oro-pharyngeal stimulation by OPAMM, prior to gavage feeding, significantly increased motilin hormone and possibly increased secretin and cholecystokinin hormones.

Microbiota-independent immunological effects of non-digestible oligosaccharides in the context of inflammatory bowel diseases

The aim of the present paper is to review the effects of non-digestible oligosaccharides (NDO) on immunity, focusing on their microbiota-independent mechanisms of action, as well as to explore their potential beneficial role in inflammatory bowel diseases (IBD). IBD are chronic, inflammatory conditions of the gastrointestinal tract. Individuals with IBD have an aberrant immune response to commensal microbiota, resulting in extensive mucosal inflammation and increased intestinal permeability. NDO are prebiotic fibres well known for their role in supporting intestinal health through modulation of the gut microbiota. NDO reach the colon intact and are fermented by commensal bacteria, resulting in the production of SCFA with immunomodulatory properties. In disease states characterised by increased gut permeability, prebiotics may also bypass the gut barrier and directly interact with intestinal and systemic immune cells, as demonstrated in patients with IBD and in infants with an immature gut. In vitro models show that fructooligosaccharides, inulin and galactooligosaccharides exert microbiota-independent effects on immunity by binding to toll-like receptors on monocytes, macrophages and intestinal epithelial cells and by modulating cytokine production and immune cell maturation. Moreover, animal models and human supplementation studies demonstrate that some prebiotics, including inulin and lactulose, might reduce intestinal inflammation and IBD symptoms. Although there are convincing preliminary data to support NDO as immunomodulators in the management of IBD, their mechanisms of action are still unclear and larger standardised studies need to be performed using a wider range of prebiotics.

Pathophysiology of Gastroesophageal Reflux Disease in Infants and Nonpharmacologic Strategies for Symptom Management

Gastroesophageal reflux is common in young infants, particularly those born prematurely or with a history of medical complexity. The most recent clinical practice guidelines recommend the use of nonpharmacologic management strategies because of concerns about the safety of acid-reducing medications and a lack of evidence of their effectiveness. Our purpose in this article is to holistically review the pathophysiology of gastroesophageal reflux disease, identify symptom management targets, and describe nonpharmacologic strategies that nurses can implement and/or teach to parents to manage symptoms of gastroesophageal reflux. Strategies targeting stress, dysbiosis, food intolerances, feeding difficulties, and positioning are discussed. Nurses can work with families to identify factors contributing to gastroesophageal reflux disease and determine individualized strategies that can be used in lieu of, or in addition to, medication.

Adequacy of Parenteral Nutrition in Preterm Infants According to Current Recommendations: A Study in A Spanish Hospital

Background: In preterm infants, it is important to ensure adequate nutritional intake to accomplish foetal growth requirements. This study evaluated clinical practice regarding the prescription of parenteral nutrition in preterm infants in the neonatology unit of a tertiary hospital. Methods: It was a retrospective observational study of a sample of preterm infants (n = 155) born between January 2015 and December 2017 who were prescribed parenteral nutrition. Compliance with the hospital’s protocol and with the guidelines of the scientific societies American Society for Parenteral and Enteral Nutrition (ASPEN), European Society for Clinical Nutrition and Metabolism (ESPEN) and Spanish Society of Clinical Nutrition and Metabolism (SENPE) was evaluated. The differences in macronutrient intake and total duration of parenteral nutrition were analysed according to gestational age and birth weight. Results: The established protocol was followed in a high percentage (95.5%–100%) except with respect to the initiation of supplying established trace elements (64.9%). Compliance with the recommendations set forth in the guidelines was between 82.1% and 100%, with the exception of the initial carbohydrate intake recommended by ASPEN and ESPEN, for which compliance was 8.3%. Lower gestational age and birth weight were correlated with longer duration of parenteral nutrition (p < 0.001). Conclusions: A lower gestational age and birth weight are related to a longer duration of parenteral nutrition. The results of this study demonstrate the importance of developing and evaluating protocols in clinical practice.

Effects of early commercial milk supplement on the mucosal morphology, bacterial community and bacterial metabolites in jejunum of the pre- and post-weaning piglets

Objective

Sow milk (SM) may not be able to meet the piglet’s nutritional needs in late lactation. Hence, this study was conducted to investigate the effects of early commercial milk (CM) supplement on the mucosal morphology, bacterial community and bacterial metabolites in jejunum of piglets.

Methods

Ten litters of newborn piglets ([Yorkshire×Landrace]×Duroc) were randomly divided into 2 groups of 5 litters. The piglets in the control group were suckled by the sow (SM), while the piglets in the treatment group (CM supplement) were supplemented with a CM supplement along with suckling from d 4 to d 28 of age.

Results

No significant differences were observed about jejunal mucosal morphology on d 28 and d 35 between two groups. On d 28, the activity of lactase in the jejunum was significantly decreased in the CM group, while the activity of sucrase and the ratio of maltase to lactase were significantly increased (p<0.05). On d 35, the activity of maltase in the jejunum was significantly increased in the CM group (p<0.05), and maltase to lactase ratio tended to increase in the CM group (p = 0.065). In addition, piglets in the CM group had a higher abundance of Clostridium XI, Tuicibater, and Moraxella in the jejunum on d 28, while the abundance of Lactobacillus was significantly increased on d 35 (p<0.05).

Conclusion

The early CM supplement improved the maturation of the jejunum to some extent by enhancing the maltase and sucrase activities. Moreover, the early CM supplement could help maintain the homeostasis of internal environment in jejunum by increasing the microbial-derived metabolites.

Nutrition, Growth, Brain Volume, and Neurodevelopment in Very Preterm Children

OBJECTIVE

To explore the associations between nutrition in the first 28 days after birth with somatic growth from birth to term-equivalent age, brain volumes at term-equivalent age, and neurodevelopment at 24 months of corrected age.

STUDY DESIGN

Prospective cohort study of 149 infants born from 2011 to 2014 at <30 weeks of gestation in a tertiary neonatal nursery in Australia. The following data were collected: average daily energy, protein, fat, and carbohydrate intakes from birth until 28 days, and the difference in weight and head circumference z scores between birth and term-equivalent. Total brain tissue volumes were calculated from brain magnetic resonance imaging at term-equivalent age. Children were assessed at 2 years of corrected age with the Bayley Scales of Infant and Toddler Development-Third Edition. Relationships of nutritional variables with growth, brain volumes, and cognitive, language, and motor development were explored using linear regression.

RESULTS

Complete nutritional data were available for 116 (78%) of the cohort. A 1 g/kg/day higher mean protein intake was associated with a mean increase in weight z score per week of 0.05 (95% CI 0.05, 0.10; P = .04). There was a lack of evidence for associations of any nutritional variables with head circumference growth, with brain volumes at term-equivalent age, or with 2-year neurodevelopment.

CONCLUSIONS

Only higher protein intakes in the first 28 days after birth were associated with better weight growth between birth and term-equivalent age in very preterm infants. Nutrition in the first 28 days was otherwise not substantially related to brain size or to neurodevelopmental outcomes.

The Preterm Gut Microbiota: An Inconspicuous Challenge in Nutritional Neonatal Care

The nutritional requirements of preterm infants are unique and challenging to meet in neonatal care, yet crucial for their growth, development and health. Normally, the gut microbiota has distinct metabolic capacities, making their role in metabolism of dietary components indispensable. In preterm infants, variation in microbiota composition is introduced while facing a unique set of environmental conditions. However, the effect of such variation on the microbiota's metabolic capacity and on the preterm infant's growth and development remains unresolved. In this review, we will provide a holistic overview on the development of the preterm gut microbiota and the unique environmental conditions contributing to this, in addition to maturation of the gastrointestinal tract and immune system in preterm infants. The role of prematurity, as well as the role of human milk, in the developmental processes is emphasized. Current research stresses the early life gut microbiota as cornerstone for simultaneous development of the gastrointestinal tract and immune system. Besides that, literature provides clues that prematurity affects growth and development. As such, this review is concluded with our hypothesis that prematurity of the gut microbiota may be an inconspicuous clinical challenge in achieving optimal feeding besides traditional challenges, such as preterm breast milk composition, high nutritional requirements and immaturity of the gastrointestinal tract and immune system. A better understanding of the metabolic capacity of the gut microbiota and its impact on gut and immune maturation in preterm infants could complement current feeding regimens in future neonatal care and thereby facilitate growth, development and health in preterm infants.

Physiology of the Neonatal Gastrointestinal System Relevant to the Disposition of Orally Administered Medications

A thorough knowledge of the newborn (age, birth to 1 month postpartum) infant's gastrointestinal tract (GIT) is critical to the evaluation of the absorption, distribution, metabolism, and excretion (ADME) of orally administered drugs in this population. Developmental changes in the GIT during the newborn period are important for nutrient uptake as well as the disposition of orally administered medications. Some aspects of gastrointestinal function do not mature until driven by increased dietary complexity and nutritional demands later in the postnatal period. The functionalities present at birth, and subsequent maturation, can also impact the ADME parameters of orally administered compounds. This review will examine some specific contributors to the ADME processes in human neonates, as well as what is currently understood about the drivers for their maturation. Key species differences will be highlighted, with a focus on laboratory animals used in juvenile toxicity studies. Because of the gaps and inconsistencies in our knowledge, we will also highlight areas where additional study is warranted to better inform the appropriate use of medicines specifically intended for neonates.

Establishment of an ideal gut microbiota to boost healthy growth of neonates

For decades, supporting the optimal growth of low birth weight (LBW) infants has been considered one of the most important paediatric challenges, despite advances in neonatal intensive care technology and nutrition interventions. Since gut microbiota affects such diverse phenotypes in adults, the difference in gut microbiota composition between normal infants and LBW infants raises the possibility of gut microbiota playing an important role in different growth rates of neonates. Based on the concept that probiotics are generally beneficial to the health, numerous studies have been made on probiotics as a supplement to the diet of the LBW infants. However, clinical results on the effects of probiotics on LBW infant growth are either inconsistent or contradictory with each other, and thus the contribution of gut microbiota in neonatal growth has remained inconclusive. In this review, recent researches on neonatal gut microbiota are discussed to develop a new strategy for targeting gut microbiota as a solution to growth retardation in LBW infants. We also discuss how to establish the ideal gut microbiota to support optimal growth of LBW infants.

Nutritional Support Strategies for the Preterm Infant in the Neonatal Intensive Care Unit

The goal of nutrition of the preterm infant is to "provide nutrients to approximate the rate of growth and composition of weight gain for a normal fetus of the same postmenstrual age and to maintain normal concentrations of blood and tissue nutrients" (American Academy of Pediatrics 2014). Failure to provide the necessary amounts of all of the essential nutrients to preterm infants has produced not only growth failure, but also increased morbidity and less than optimal neurodevelopment. This continues to be true despite many efforts to increase nutrition of the preterm infants. In contrast, enhanced nutrition of very preterm infants, both intravenous and enteral, beginning right after birth, promotes positive energy and protein balance and improves longer term neurodevelopmental outcomes. The benefits are long lasting too, particularly for prevention of later life chronic diseases.

Gastrointestinal mucosal development and injury in premature lambs supported by the artificial placenta

BACKGROUND

An Artificial Placenta (AP) utilizing extracorporeal life support (ECLS) could revolutionize care of extremely premature newborns, but its effects on gastrointestinal morphology and injury need investigation.

METHODS

Lambs (116-121days GA, term=145; n=5) were delivered by C-section, cannulated for ECLS, had total parenteral nutrition (TPN) provided, and were supported for 7days before euthanasia. Early and Late Tissue Controls (ETC, n=5 and LTC, n=5) delivered at 115-121days and 125-131days, respectively, were immediately sacrificed. Standardized jejunal samples were formalin-fixed for histology. Crypt depth (CD), villus height (VH), and VH:CD ratios were measured. Measurements also included enterocyte proliferation (Ki-67), Paneth cell count (Lysozyme), and injury scores (H&E). ANOVA and Chi Square were used with p<0.05 considered significant.

RESULTS

CD, VH, and VH:CD were similar between groups (p>0.05). AP demonstrated more enterocyte proliferation (95.7±21.8) than ETC (49.4±23.4; p=0.003) and LTC (66.1+11.8; p=0.04), and more Paneth cells (81.7±17.5) than ETC (41.6±7.0; p=0.0005) and LTC (40.7±8.2, p=0.0004). Presence of epithelial injury and congestion in the bowel of all groups were not statistically different. No villus atrophy or inflammation was present in any group.

CONCLUSIONS

This suggests preserved small bowel mucosal architecture, high cellular turnover, and minimal evidence of injury.

STUDY TYPE

Research paper/therapeutic potential.

LEVEL OF EVIDENCE

N/A.

Nutrient Fortification of Human Donor Milk Affects Intestinal Function and Protein Metabolism in Preterm Pigs

Background

Nutrient fortification of human milk is often required to secure adequate growth and organ development for very preterm infants. There is concern that formula-based fortifiers (FFs) induce intestinal dysfunction, feeding intolerance, and necrotizing enterocolitis (NEC). Bovine colostrum (BC) may be an alternative nutrient fortifier, considering its high content of protein and milk bioactive factors.

Objective

We investigated whether BC was superior to an FF product based on processed bovine milk and vegetable oil to fortify donor human milk (DHM) for preterm pigs, used as a model for infants.

Methods

Sixty preterm pigs from 4 sows (Danish Landrace × Large White × Duroc, birth weight 944 ± 29 g) received decreasing volumes of parenteral nutrition (96-72 mL ⋅ kg-1 ⋅ d-1) and increasing volumes of enteral nutrition (24-132 mL ⋅ kg-1 ⋅ d-1) for 8 d. Pigs were fed donor porcine milk (DPM) and DHM with or without FF or BC fortification (+4.6 g protein ⋅ kg-1 ⋅ d-1).

Results

DPM-fed pigs showed higher growth (10-fold), protein synthesis (+15-30%), villus heights, lactase and peptidase activities (+30%), and reduced intestinal cytokines (-50%) relative to DHM pigs (all P < 0.05). Fortification increased protein synthesis (+20-30%), but with higher weight gain and lower urea and cortisol concentrations for DHM+BC compared with DHM+FF pigs (2- to 3-fold differences, all P ≤ 0.06). DHM+FF pigs showed more diarrhea and reduced lactase and peptidase activities, hexose uptake, and villus heights relative to DHM+BC or DHM pigs (30-90% differences, P < 0.05). Fortification did not affect NEC incidence but DHM+BC pigs had lower colonic interleukin (IL)-6 and IL-8 concentrations relative to the remaining pigs (-30%, P = 0.06). DHM+FF pigs had higher stomach bacterial load than did DHM, and higher bacterial density along intestinal villi than did DHM and DHM+BC pigs (2- to 3-fold, P < 0.05).

Conclusions

The FF product investigated in this study reduced growth, intestinal function, and protein utilization in DHM-fed preterm pigs, relative to BC as fortifier. The relevance of BC as an alternative nutrient fortifier for preterm infants should be tested.

Bioactive Whey Protein Concentrate and Lactose Stimulate Gut Function in Formula-fed Preterm Pigs

OBJECTIVE

Formula feeding is associated with compromised intestinal health in preterm neonates compared with maternal milk, but the mechanisms behind this are unclear. We hypothesized that the use of maltodextrin and whey protein concentrates (WPCs) with reduced bioactivity owing to thermal processing are important factors.

METHOD

Ninety-two cesarean-delivered preterm pigs were fed increasing doses of formulas for 5 days (24-120 mL · kg · day). In experiment 1, 4 groups of pigs (n = 15-16) were fed lactose- or maltodextrin-dominant formulas (lactose/maltodextrin ratios 3:1 or 1:3, respectively), containing WPC with either high or low levels of IgG (WPC1 or WPC2, respectively). In experiment 2, 2 groups of pigs (n = 15-16) were fed lactose-dominant formulas with either a bioactive WPC (BioWPC, produced by reduced thermal-processing) or a conventional WPC (ConWPC).

RESULTS

In experiment 1, pigs fed formula with WPC1 had higher villi, hexose absorption, and lactase activity in small intestine, relative to WPC2, but predominantly with the lactose-dominant formula (all P < 0.05). In experiment 2, the BioWPC product had higher bioactivity, as indicated by higher IgG, lactoferrin, and TGF-β2 levels, and better enterocyte proliferation in vitro. Pigs fed the BioWPC formula showed better feeding tolerance and higher intestinal villi and lactase activity (all P < 0.05). The BioWPC formula-fed pigs also had greater physical activity (P < 0.05 on day 4) and tended to show improved hexose absorption and decreased gut permeability (both P ≤ 0.09).

CONCLUSIONS

Infant formulas containing lactose as the main carbohydrate, and WPC with reduced thermal processing, may support gut maturation and health in sensitive, preterm neonates.

Improved nutrition for extremely preterm infants - A population based observational study

BACKGROUND AND AIMS

Extremely preterm (EPT) infants are at high risk for malnutrition due to immaturity and medical complications and they often accumulate nutritional deficits and experience growth faltering during treatment at neonatal intensive care units (NICUs). Enhanced intake of energy and protein during the first weeks of life improves weight gain and head circumference growth. The optimal nutritional strategy for these infants' health and long-term development remains unknown. Nutritional regiments have been identified as a potential area for improvement in Swedish NICUs. The aim of this study was to evaluate changes in nutritional intake over time during the first 56 postnatal days in EPT (<27 gestational weeks; n = 316) infants, who were treated in NICUs during 2004-2011 in Stockholm, using a population-based study approach.

METHODS

Several different nutritional interventions were implemented over the 8-year period. Nutrition and growth data were obtained retrospectively from hospital records. All intakes of enteral and parenteral nutrients were retrieved daily during the first 28 postnatal days and on days 35, 42, 49 and 56.

RESULTS

Energy intake (median) increased from 77 kcal/kg/d during the 2004-2005 period to 98 kcal/kg/d during the 2010-2011 period on days 4-6. Median protein intake increased from 2.4 g/kg/d during 2004-2005 to 3.6 g/kg/d during 2010-2011. Energy and protein intake during postnatal days 0-6 increased continuously over the 8 years and protein intake increased during all 56 postnatal days. Full enteral feeds were reached earlier and the proportion of enteral feeds during the first week was higher during 2008-2009 compared to all other years. A significant improvement in growth was primarily noted by comparing the 2004-2005 period to subsequent years.

CONCLUSIONS

Neonatal nutrition improved significantly in Stockholm from 2004 to 2011. Above all, parenteral nutrition was initiated more promptly during the first week and was provided at higher quantities. However, many of the EPT infants born during the later years still did not reach the recommended macronutrient intake levels. A significant weight gain improvement was observed between 2004-2005 and 2006-2011.

Protective effects of amniotic fluid in the setting of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is the most common life threatening condition affecting preterm infants. NEC occurs in 1-5% of all neonatal intensive care admissions and 5-10% of very low birth weight infants. The protective role of human breast milk (BM) has been well established. It has also been shown that amniotic fluid (AF) and BM have many similarities in terms of presence of growth and other immune-modulatory factors. This finding led to the initial hypothesis that AF may exert similar protective effects against the development of NEC, as does BM. Multiple studies have elucidated the presence of growth factors in AF and the protective effect of AF against NEC. Studies have also described possible mechanisms how AF protects against NEC. At present, research in this particular area is extremely active and robust. This review summarizes the various studies looking at the protective effects of AF against the development of NEC. It also provides an insight into future directions, the vast potential of AF as a readily available biologic medium, and the ethical barriers that must be overcome before using AF.

Optimizing nutrition of the preterm infant

The goal of nutrition of the preterm infant is to meet the growth rate of the healthy fetus of the same gestational age and to produce the same body composition of the healthy fetus in terms of organ growth, tissue components, and cell number and structure. Nutritional quantity and quality are fundamental for normal growth and development of preterm infants, including neurodevelopmental outcomes. Failure to provide the necessary amounts of all of the essential nutrients has produced not only growth failure, but also increased morbidity and less than optimal neurodevelopment. Growth velocities during the NICU hospitalization period for preterm infants exert a significant effect on neurodevelopmental and anthropometric outcomes. Despite the obvious need for optimal nutrition, growth failure is almost universal among preterm infants. There is every reason, therefore, to optimize nutrition of the preterm infant, in terms of total energy and protein, but also in terms of individual components such as amino acids, specific carbohydrates and lipids, and even oxygen. This review presents scientific rationale for nutrient requirements and practical guidelines and approaches to intravenous and enteral feeding for preterm infants. Intravenous feeding, including amino acids, should be started right after birth at rates that are appropriate for the gestational age of the infant. Enteral feeding should be started as soon as possible after birth, using mother's colostrum and milk as first choices. Enteral feeding should begin with trophic amounts and advanced as rapidly as tolerated, decreasing IV nutrition accordingly, while maintaining nutrient intakes at recommended rates. Feeding protocols are valuable for improving nutrition and related outcomes. Further research is needed to determine the optimal nutrition and rate of growth in preterm infants that will achieve optimal neurocognitive benefits while minimizing the longer-term risk of chronic diseases.

Global hypoxia-ischemia induced inflammation and structural changes in the preterm ovine gut which were not ameliorated by mesenchymal stem cell treatment

Perinatal asphyxia, a condition of impaired gas exchange during birth, leads to fetal hypoxia-ischemia (HI) and is associated with postnatal adverse outcomes including intestinal dysmotility and necrotizing enterocolitis (NEC). Evidence from adult animal models of transient, locally-induced intestinal HI has shown that inflammation is essential in HI-induced injury of the gut. Importantly, mesenchymal stem cell (MSC) treatment prevented this HI-induced intestinal damage. We therefore assessed whether fetal global HI induced inflammation, injury and developmental changes in the gut and whether intravenous MSC administration ameliorated these HI-induced adverse intestinal effects. In a preclinical ovine model, fetuses were subjected to umbilical cord occlusion (UCO), with or without MSC treatment, and sacrificed 7 days after UCO. Global HI increased the number of myeloperoxidase positive cells in the mucosa, upregulated mRNA levels of interleukin (IL)-1β and IL-17 in gut tissue and caused T-cell invasion in the intestinal muscle layer. Intestinal inflammation following global HI was associated with increased Ki67+ cells in the muscularis and subsequent muscle hyperplasia. Global HI caused distortion of glial fibrillary acidic protein immunoreactivity in the enteric glial cells and increased synaptophysin and serotonin expression in the myenteric ganglia. Intravenous MSC treatment did not ameliorate these HI-induced adverse intestinal events. Global HI resulted in intestinal inflammation and enteric nervous system abnormalities which are clinically associated with postnatal complications including feeding intolerance, altered gastrointestinal transit and NEC. The intestinal histopathological changes were not prevented by intravenous MSC treatment directly after HI, indicating that alternative treatment regimens for cell-based therapies should be explored.

Galectins are human milk glycan receptors

The biological recognition of human milk glycans (HMGs) is poorly understood. Because HMGs are rich in galactose we explored whether they might interact with human galectins, which bind galactose-containing glycans and are highly expressed in epithelial cells and other cell types. We screened a number of human galectins for their binding to HMGs on a shotgun glycan microarray consisting of 247 HMGs derived from human milk, as well as to a defined HMG microarray. Recombinant human galectins (hGal)-1, -3, -4, -7, -8 and -9 bound selectively to glycans, with each galectin recognizing a relatively unique binding motif; by contrast hGal-2 did not recognize HMGs, but did bind to the human blood group A Type 2 determinants on other microarrays. Unlike other galectins, hGal-7 preferentially bound to glycans expressing a terminal Type 1 (Galβ1-3GlcNAc) sequence, a motif that had eluded detection on non-HMG glycan microarrays. Interactions with HMGs were confirmed in a solution setting by isothermal titration microcalorimetry and hapten inhibition experiments. These results demonstrate that galectins selectively bind to HMGs and suggest the possibility that galectin-HMG interactions may play a role in infant immunity.

Signs and symptoms associated with digestive tract development

OBJECTIVE

To analyze the development and prevalence of gastrointestinal signs and symptoms associated with the development of the digestive tract, and to assess the measures aimed to reduce their negative impacts.

SOURCE OF DATA

Considering the scope and comprehensiveness of the subject, a systematic review of the literature was not carried out. The Medline database was used to identify references that would allow the analysis of the study topics.

SYNTHESIS OF RESULTS

Infants frequently show several gastrointestinal signs and symptoms. These clinical manifestations can be part of gastrointestinal functional disorders such as infantile colic, infant regurgitation, and functional constipation. Allergy to cow's milk protein and gastroesophageal reflux disease are also causes of these clinical manifestations and represent an important and difficult differential diagnosis. The diseases that course with gastrointestinal signs and symptoms can have an impact on family dynamics and maternal emotional status, and may be associated with future problems in the child's life. Comprehensive pediatric care is essential for diagnosis and treatment. Maternal breastfeeding should always be maintained. Some special formulas can contribute to the control of clinical manifestations depending on the established diagnosis.

CONCLUSION

During the normal development of the digestive tract, several gastrointestinal signs and symptoms may occur, usually resulting from functional gastrointestinal disorders, gastroesophageal reflux disease, and allergy to cow's milk protein. Breastfeeding should always be maintained.

Daily Breastmilk Volume in Mothers of Very Low Birth Weight Neonates: A Repeated-Measures Randomized Trial of Hand Expression Versus Electric Breast Pump Expression

BACKGROUND

There are no randomized trials comparing early exclusive hand expression (HE) with early exclusive electric pump expression (electric expression [EE]) for milk removal in mothers of very low birth weight (VLBW) infants.

SUBJECTS AND METHODS

Mothers of VLBW infants were randomized to exclusively HE or EE for the first 7 days postpartum. Daily volumes of milk were compared between groups for the first 28 days, adjusting for repeated measures.

RESULTS

The HE (n=12) and the EE (n=14) groups did not differ with respect to age, parity, single versus multiple gestation, or number of expression sessions per day. There were 728 values for daily milk volumes in the first 28 days, including 105 HE and 623 EE. Mothers using exclusive HE had significantly (p<0.05) less cumulative daily milk production throughout the first 7 days postpartum compared with exclusive EE. Mean cumulative milk production among mothers using HE in the first postpartum week remained approximately half that of those using the electric pump throughout the first 28 days, without evident catch up. In multivariable analysis, each postpartum day was associated with an adjusted increase of 50 mL of human milk/day during the first 7 days postpartum and an increase of 13 mL/day between postpartum Days 8 and 28. After adjusting for repeated measures, number of expression sessions per day, and postpartum day, EE was associated with an advantage in milk production of 119 mL/day during the first 28 postpartum days compared with HE.

CONCLUSIONS

Compared with mothers using EE, mothers using HE had significantly less cumulative daily milk production during the first 7 days postpartum. This trend continued after the intervention had been discontinued, and the great majority of expressions in both groups were with EE. Further research to confirm and expand these findings is warranted.

Production of human lactoferrin and lysozyme in the milk of transgenic dairy animals: past, present, and future

Genetic engineering, which was first developed in the 1980s, allows for specific additions to animals' genomes that are not possible through conventional breeding. Using genetic engineering to improve agricultural animals was first suggested when the technology was in the early stages of development by Palmiter et al. (Nature 300:611-615, 1982). One of the first agricultural applications identified was generating transgenic dairy animals that could produce altered or novel proteins in their milk. Human milk contains high levels of antimicrobial proteins that are found in low concentrations in the milk of ruminants, including the antimicrobial proteins lactoferrin and lysozyme. Lactoferrin and lysozyme are both part of the innate immune system and are secreted in tears, mucus, and throughout the gastrointestinal (GI) tract. Due to their antimicrobial properties and abundance in human milk, multiple lines of transgenic dairy animals that produce either human lactoferrin or human lysozyme have been developed. The focus of this review is to catalogue the different lines of genetically engineered dairy animals that produce either recombinant lactoferrin or lysozyme that have been generated over the years as well as compare the wealth of research that has been done on the in vitro and in vivo effects of the milk they produce. While recent advances including the development of CRISPRs and TALENs have removed many of the technical barriers to predictable and efficient genetic engineering in agricultural species, there are still many political and regulatory hurdles before genetic engineering can be used in agriculture. It is important to consider the substantial amount of work that has been done thus far on well established lines of genetically engineered animals evaluating both the animals themselves and the products they yield to identify the most effective path forward for future research and acceptance of this technology.

A 6th Vital Sign--Potential Use of Nasogastric Tube for Intra-abdominal Pressure Monitoring Method to Detect Feeding Intolerance in Very Low Birth-Weight Preterm Infants (<1500 g)

BACKGROUND

While various feeding strategies designed to optimize growth have been investigated and used in the clinical setting, the problem of not being able to recognize the warning signs of feeding intolerance early enough to prevent serious gastrointestinal complication commonly associated with very low birth-weight (VLBW) preterm infant remains. Currently, early stages of feeding intolerance are most often identified though nurse assessments. Additional methods to predict feeding intolerance in this population are needed. Currently, intra-abdominal pressure monitoring has been an effective method to predict intolerance to enteral nutrition in the adult and pediatric populations.

PURPOSE

There is supportive evidence for the use of noninvasive methods, such as nasogastric tubes, to effectively monitor IAP. While this may not be the gold standard method of using Foley catheters for measurement, it could provide predictive levels that are indicative of progression toward bowel inflammation.

FINDINGS

This review shows the potential for using noninvasive nasogastric tubes for monitoring intra-abdominal pressure and may provide direction for evaluating intra-abdominal pressures in VLBW preterm infants as a reliable method for early identification of feeding intolerance.

IMPLICATIONS FOR PRACTICE

The use of nasogastric tubes to monitor intra-abdominal pressure may provide an effective noninvasive tool to identify VLBW preterm infants progressing toward feeding intolerance and would add to assessment data.

IMPLICATIONS FOR RESEARCH

Development and testing of a reliable nasogastric tube monitoring device in the VLBW preterm infant population and identify predictive levels that indicate progression toward feeding intolerance is needed. Once IAP predictive levels are identified, provider interventions could be developed.

Provision of Amniotic Fluid During Parenteral Nutrition Increases Weight Gain With Limited Effects on Gut Structure, Function, Immunity, and Microbiology in Newborn Preterm Pigs

BACKGROUND

Small enteral boluses with human milk may reduce the risk of subsequent feeding intolerance and necrotizing enterocolitis in preterm infants receiving parenteral nutrition (PN). We hypothesized that feeding amniotic fluid, the natural enteral diet of the mammalian fetus, will have similar effects and improve growth and gastrointestinal (GI) maturation in preterm neonates receiving PN, prior to the transition to milk feeding.

MATERIALS AND METHODS

Twenty-seven pigs, delivered by cesarean section at ~90% of gestation, were provided with PN and also fed boluses with amniotic fluid (AF; n = 13, 24-72 mL/kg/d) or no oral supplements (nil per os [NPO]; n = 14) until day 5 when blood, tissue, and fecal samples were collected for analyses.

RESULTS

Body weight gain was 2.7-fold higher in AF vs NPO pigs. AF pigs showed slower gastric emptying, reduced meal-induced release of gastric inhibitory peptide and glucagon-like peptide 2, changed gut microbiota, and reduced intestinal permeability. There were no effects on GI weight, percentage mucosa, villus height, plasma citrulline, hexose absorptive capacity, and digestive enzymes. Intestinal interleukin (IL)-1β levels and expression of IL1B and IL8 were increased in AF pigs, while blood biochemistry and amino acid levels were minimally affected.

CONCLUSION

Enteral boluses of AF were well tolerated in the first 5 days of life in preterm pigs receiving PN. Enteral provision of AF before the initiation of milk feeding may stimulate body growth and improve hydration in preterm infants receiving PN. Furthermore, it may improve GI motility and integrity, although most markers of GI maturation remain unchanged.

Specificity of infant digestive conditions: some clues for developing relevant in vitro models

Digestion of nutrients is an essential function of the newborn infant gut to allow growth and development and understanding infant digestive function is essential to optimize nutrition and oral drug delivery. Ethical considerations prohibit invasive in vivo trials and as a consequence in vitro assays are often conducted. However, the choice of in vitro model parameters are not supported by an exhaustive analysis of the literature and do not mimic precisely the digestive conditions of the infant. This review contains a compilation of the studies which characterized the gastroduodenal conditions in full-term or preterm infants of variable postnatal age from birth up to six months. Important data about healthy full-term infants are reported. The enzymatic (type of enzymes and level of activity) and nonenzymatic (milk-based diet, frequency of feeding, bile salt concentrations) conditions of digestion in infants are shown to differ significantly from those in adults. In addition, the interindividual and developmental variability of the digestive conditions in infants is also highlighted.

Gastrointestinal ultrasonography of normal Standardbred neonates and frequency of asymptomatic intussusceptions

Background

Ultrasonographic appearance of the gastrointestinal (GI) tract of equine neonates has not been completely described.

Objectives

To describe (1) sonographic characteristics of the GI segments in normal nonsedated equine neonates, (2) intra‐ and interobserver variation in wall thickness, and (3) the sonographic appearance of asymptomatic intussusceptions, and (4) to compare age and sonographic findings of foals with and without asymptomatic intussusceptions.

Animals

Eighteen healthy Standardbred foals ≤5 days of age.

Methods

Prospective, cross‐sectional blinded study. Gastrointestinal sonograms were performed stall‐side. Intraobserver variability in wall thickness measurements was determined by calculating the coefficient of variation (CV). The Bland–Altman method was used to assess interobserver bias. Student's t‐test and Fisher's exact test were used to test the association among presence of intussusceptions, age, and selected sonographic findings.

Results

The reference ranges (95% predictive interval) for wall thickness were 1.6–3.6 mm for the stomach, 1.9–3.2 mm for the duodenum, 1.9–3.1 mm for the jejunum, 1.3–2.2 mm for the colon, and 0.8–2.7 mm for the cecum. Intraobserver wall thickness CV ranged from 8 to 21% for the 2 observers for 5 gastrointestinal segments. The interobserver bias for wall thickness measurements was not significant except for the stomach (0.14 mm, P < .05) and duodenum (0.29 mm, P < .05). Diagnostic images of mural blood flow could not be obtained. Asymptomatic intussusceptions were found in 10/18 neonates. Associations between sonographic variables or age and the presence of intussusceptions were not found.

Conclusions and Clinical Importance

Sonographic characteristics of the GI tract of normal Standardbred neonates can be useful in evaluating ill foals. Asymptomatic small intestinal intussusceptions occur in normal Standardbred neonates.

Short bowel syndrome in infants: the critical role of luminal nutrients in a management program

Short bowel syndrome develops when the remnant mass of functioning enterocytes following massive resections cannot support growth or maintain fluid–electrolyte balance and requires parenteral nutrition. Resection itself stimulates the intestine’s inherent ability to adapt morphologically and functionally. The capacity to change is very much related to the high turnover rate of enterocytes and is mediated by several signals; these signals are mediated in large part by enteral nutrition. Early initiation of enteral feeding, close clinical monitoring, and ongoing assessment of intestinal adaptation are key to the prevention of irreversible intestinal failure. The length of the functional small bowel remnant is the most important variable affecting outcome. The major objective of intestinal rehabilitation programs is to achieve early oral nutritional autonomy while maintaining normal growth and nutrition status and minimizing total parenteral nutrition related comorbidities such as chronic progressive liver disease. Remarkable progress has been made in terms of survivability and quality of life, especially in the context of coordinated multidisciplinary programs, but much work remains to be done.

Non-invasive analysis of intestinal development in preterm and term infants using RNA-Sequencing

The state and development of the intestinal epithelium is vital for infant health, and increased understanding in this area has been limited by an inability to directly assess epithelial cell biology in the healthy newborn intestine. To that end, we have developed a novel, noninvasive, molecular approach that utilizes next generation RNA sequencing on stool samples containing intact epithelial cells for the purpose of quantifying intestinal gene expression. We then applied this technique to compare host gene expression in healthy term and extremely preterm infants. Bioinformatic analyses demonstrate repeatable detection of human mRNA expression, and network analysis shows immune cell function and inflammation pathways to be up-regulated in preterm infants. This study provides incontrovertible evidence that whole-genome sequencing of stool-derived RNA can be used to examine the neonatal host epithelial transcriptome in infants, which opens up opportunities for sequential monitoring of gut gene expression in response to dietary or therapeutic interventions.

Reduced plasma citrulline levels in low birth weight infants with necrotizing enterocolitis

BACKGROUND

Citrulline, a nonprotein amino acid, is an intermediate of the urea cycle and synthesized in small intestine. Lower plasma citrulline levels were associated with reduced function of enterocytes. Necrotizing enterocolitis (NEC) causes high morbidity and mortality, and leads impaired intestinal functions.

METHODS

Plasma citrulline levels of neonates with a gestational age <32 weeks and ≤1,500 gm who developed NEC stage II/III were measured by high-performance liquid chromatography.

RESULTS

We enrolled 36 preterm infants including 20 with NEC and 16 controls. Median citrulline levels of NEC and control groups were 8.6 and 20.18 μmol/l (P < 0.05), and cut off level of citrulline was 13.15 μmol/l with a sensitivity of 80% and a specificity of 82%. Median arginine levels of NEC and control groups were 22.02 and 39.89 μmol/l (P < 0.05), and cut off level of arginine was 28.52 μmol/l with a sensitivity of 70% and a specificity of 75%. Blood sampling day, gender, parenteral, and enteral nutrition did not affect the amino acid levels.

CONCLUSION

We found lower plasma citrulline and arginine levels in preterm infants with NEC. Further studies are needed to determine most appropriate levels to predict recovery and prognosis of NEC, and treatment options with these amino acids in preterm infants.

Challenges in the practice of human milk nutrition in the neonatal intensive care unit

The use of human milk for preterm infants has increased over the past decade reflecting an improved awareness of the benefits of human milk. Inherent in this paradigm shift is the recognition that human milk is a living tissue; full of immune cells, probiotics and hundreds of compounds that confer bioactivity and immune protective properties. Together these factors deliver a powerful effect in reducing clinical morbidities such as necrotizing enterocolitis and sepsis in the preterm infant. However, as breastfeeding is not possible for the very premature infant, human milk needs to be introduced in the neonatal intensive care unit through alternative means, resulting in significant handling and manipulation of maternal milk. This presents risks in quality control and provision of optimal nutrition delivery. Therefore, a comprehensive approach to standardizing preterm infant nutrition is essential to optimize the collection, storage, fortification and delivery of human milk to preterm neonates. In this paper we discuss the challenges presented by supporting human milk nutrition, and the rationale for the development of the Supporting Premature Infant Nutrition (SPIN) program at our institution.

Nutritional needs of the micropreterm infant

We have used an expansive definition of a micropreterm infant as <30 weeks' gestation to provide a global perspective to a "high risk" group of preterm infants for which there are little published data to guide nutritional management. Consensus nutritional guidelines for preterm infants have been developed for infants >1000 g birth weight and >28 weeks' gestational age. Micropreterm infants have greater nutritional deficits at birth than more mature preterm infants and accumulate greater postnatal deficits. Nutritional guidelines based on the needs of preterm infants born >28 weeks' gestation are unlikely, on a theoretical basis, to meet nutritional requirements of micropreterm infants. Unfortunately, very few good quality studies have addressed the nutritional requirements of this group specifically; this makes it difficult to formulate solid, evidence-based nutritional recommendations for these neonates. Nutritional management of micropreterm infants is based on recommendations established for preterm infants, which are adjusted after considering an infant's gestational age, birth weight, and clinical status. Minimal enteral feeding should commence on the first or second day of life, with incremental advancement and fortification of human milk when 100 mL/kg is tolerated. Early use of parenteral nutrition is recommended, ideally initiated within the first hours of life and enteral feeds are being established; this will help prevent the accumulation of nutritional deficits and incidence of growth failure. Fortified human milk should be given in order to meet nutritional requirements. When human milk is not available in sufficient quantity, a preterm formula should be given.

Colostrum-derived B and T cells as an extra-lymphoid compartment of effector cell populations in humans

Colostrum contains cellular components that convey immunological protection to offspring. In the present study the main subsets of lymphocytes present in colostrum and in peripheral blood of healthy screened mothers were compared through the evaluation of >15 different flow cytometry markers. Colostrum and peripheral blood samples were collected within 3 days after full-term delivery. Flow cytometry assays and laboratory tests were performed soon after collection. Among B cells, percentages of CD19(+)CD5(+) cells, pertaining to natural immunity system, were significantly higher in colostrum than in peripheral blood (33 vs. 5%, p = 0.047). CD4(+) T cells, effector cells (CD45RA(+)/CD27(-)) and effector memory cells (CD45RA(-)/CD27(-)) were significantly higher in colostrum (p < 0.001) than in peripheral blood, as well as activated CD4(+) T cells (HLA(-)DR(+)) (36% vs. 6% p = 0.0022) and CD4(+) terminally differentiated effector T cells (CD57(+)) (p < 0.001). With regards to CD8(+) T cells, a comparable significant increase in effector (p < 0.02) and effector memory cells (p < 0.001) was also observed. Moreover, an increased surface expression of HLA-DR and CD57 (p < 0.001) on CD8(+) T cells in colostrum was detected. Colostrum contains a different distribution of lymphocyte subsets with respect to peripheral blood from mothers, confirming the observation that lymphocytes probably migrate in milk in a selective way. Colostrum T and B lymphocytes appear to be enriched with subsets possessing effector functions or belonging to the innate immune system, what could transfer a prompt line of defence to offspring.

Paradigm of Time-sequence Development of the Intestine of Suckling Piglets with Microarray

The interaction of the genes involved in intestinal development is the molecular basis of the regulatory mechanisms of intestinal development. The objective of this study was to identify the significant pathways and key genes that regulate intestinal development in Landrace piglets, and elucidate their rules of operation. The differential expression of genes related to intestinal development during suckling time was investigated using a porcine genome array. Time sequence profiles were analyzed for the differentially expressed genes to obtain significant expression profiles. Subsequently, the most significant profiles were assayed using Gene Ontology categories, pathway analysis, network analysis, and analysis of gene co-expression to unveil the main biological processes, the significant pathways, and the effective genes, respectively. In addition, quantitative real-time PCR was carried out to verify the reliability of the results of the analysis of the array. The results showed that more than 8000 differential expression transcripts were identified using microarray technology. Among the 30 significant obtained model profiles, profiles 66 and 13 were the most significant. Analysis of profiles 66 and 13 indicated that they were mainly involved in immunity, metabolism, and cell division or proliferation. Among the most effective genes in these two profiles, CN161469, which is similar to methylcrotonoyl-Coenzyme A carboxylase 2 (beta), and U89949.1, which encodes a folate binding protein, had a crucial influence on the co-expression network.