Complementary Feeding: Recommendations for the Introduction of Allergenic Foods and Gluten in the Preterm Infant.

BACKGROUND: The aim of this systematic review is to analyze the available literature on the introduction of allergenic foods and gluten among preterm infants. METHODS: A systematic review of published studies concerning the introduction of gluten and allergenic foods in preterm infants was performed on PubMed and on the Cochrane Library. RESULTS: Of the 174 PubMed results, 15 papers were considered suitable for the review. A total of 83 records were identified through the Cochrane Library search; eight papers were included in the review. Additional papers were identified from the reference lists of included studies. A secondary search was conducted on the same databases to find recommendations and advice regarding healthy full-term infants that could be translated to preterm infants. Therefore, 59 additional papers were included in the review. CONCLUSIONS: Current guidelines for the introduction of solid food cannot be directly transposed to preterm infants. Further research is needed to provide evidence-based guidelines regarding weaning in preterm infants. To date, we can suggest that in preterm infants allergenic foods and gluten may be introduced when complementary feeding is started, any time after 4 months of corrected age, avoiding delayed introduction and irrespective of infants' relative risk of developing allergy. Avoiding large amounts of gluten during the first few weeks after gluten introduction and during infancy is advised, despite limited evidence to support this recommendation.

Effects of Total Enteral Nutrition on Early Growth, Immunity, and Neuronal Development of Preterm Infants.

The feeding of colostrum and mother's transitional milk improves immune protection and neurodevelopmental outcomes. It also helps with gut maturation and decreases the risks of infection. The supply of nutrients from human milk (HM) is not adequate for preterm infants, even though preterm mother's milk contains higher concentrations of protein, sodium, zinc, and calcium than mature HM. The human milk fortifiers, particularly those with protein, calcium, and phosphate, should be used to supplement HM to meet the necessities of preterm infants. The management of fluid and electrolytes is a challenging aspect of neonatal care of preterm infants. Trace minerals such as iron, zinc, copper, iodine, manganese, molybdenum, selenium, chromium, and fluoride are considered essential for preterm infants. Vitamins such as A, D, E, and K play an important role in the prevention of morbidities, such as bronchopulmonary dysplasia, retinopathy of prematurity, and intraventricular hemorrhage. Therefore, supplementation of HM with required nutrients is recommended for all preterm infants.

S100A8 and S100A9 Are Important for Postnatal Development of Gut Microbiota and Immune System in Mice and Infants.

BACKGROUND & AIMS: After birth, the immune system matures via interactions with microbes in the gut. The S100 calcium binding proteins S100A8 and S100A9, and their extracellular complex form, S100A8-A9, are found in high amounts in human breast milk. We studied levels of S100A8-A9 in fecal samples (also called fecal calprotectin) from newborns and during infancy, and their effects on development of the intestinal microbiota and mucosal immune system. METHODS: We collected stool samples (n = 517) from full-term (n = 72) and preterm infants (n = 49) at different timepoints over the first year of life (days 1, 3, 10, 30, 90, 180, and 360). We measured levels of S100A8-A9 by enzyme-linked immunosorbent assay and analyzed fecal microbiomes by 16S sRNA gene sequencing. We also obtained small and large intestine biopsies from 8 adults and 10 newborn infants without inflammatory bowel diseases (controls) and 8 infants with necrotizing enterocolitis and measured levels of S100A8 by immunofluorescence microscopy. Children were followed for 2.5 years and anthropometric data and medical information on infections were collected. We performed studies with newborn C57BL/6J wild-type and S100a9-/- mice (which also lack S100A8). Some mice were fed or given intraperitoneal injections of S100A8 or subcutaneous injections of Staphylococcus aureus. Blood and intestine, mesenterial and celiac lymph nodes were collected; cells and cytokines were measured by flow cytometry and studied in cell culture assays. Colon contents from mice were analyzed by culture-based microbiology assays. RESULTS: Loss of S100A8 and S100A9 in mice altered the phenotypes of colonic lamina propria macrophages, compared with wild-type mice. Intestinal tissues from neonatal S100-knockout mice had reduced levels of CX3CR1 protein, and Il10 and Tgfb1 mRNAs, compared with wild-type mice, and fewer T-regulatory cells. S100-knockout mice weighed 21% more than wild-type mice at age 8 weeks and a higher proportion developed fatal sepsis during the neonatal period. S100-knockout mice had alterations in their fecal microbiomes, with higher abundance of Enterobacteriaceae. Feeding mice S100 at birth prevented the expansion of Enterobacteriaceae, increased numbers of T-regulatory cells and levels of CX3CR1 protein and Il10 mRNA in intestine tissues, and reduced body weight and death from neonatal sepsis. Fecal samples from term infants, but not preterm infants, had significantly higher levels of S100A8-A9 during the first 3 months of life than fecal samples from adults; levels decreased to adult levels after weaning. Fecal samples from infants born by cesarean delivery had lower levels of S100A8-A9 than from infants born by vaginal delivery. S100 proteins were expressed by lamina propria macrophages in intestinal tissues from infants, at higher levels than in intestinal tissues from adults. High fecal levels of S100 proteins, from 30 days to 1 year of age, were associated with higher abundance of Actinobacteria and Bifidobacteriaceae, and lower abundance of Gammaproteobacteria-particularly opportunistic Enterobacteriaceae. A low level of S100 proteins in infants' fecal samples associated with development of sepsis and obesity by age 2 years. CONCLUSION: S100A8 and S100A9 regulate development of the intestinal microbiota and immune system in neonates. Nutritional supplementation with these proteins might aide in development of preterm infants and prevent microbiota-associated disorders in later years.

Early oral colostrum administration in preterm infants.

BACKGROUND: Early administration of colostrum may provide preterm infants with immune components. Previous studies illustrating the effects of oral colostrum (OC) have been confounded by the coincidence of enteral feedings. OBJECTIVE: To quantify OC absorption, as measured by urinary sIgA and lactoferrin, in preterm infants prior to enteral feedings. MATERIALS AND METHODS: Colostrum was obtained from mothers delivering infants ≤32 weeks and ≤1500 g. sIgA and lactoferrin were measured in infant urine, and microflora in saliva and tracheal aspirates were characterized. RESULTS: Urinary sIgA and lactoferrin were significantly greater in infants receiving OC by syringe compared to swab (p < 0.002). Urinary sIgA correlated with the total number of doses in 72 h (R2 = 43%, p < 0.01). CONCLUSIONS: Administration of OC by syringe and higher cumulative dose are associated with increased absorption of sIgA and lactoferrin, and early dosing may contribute to a more diverse tracheal microbiome.

Docosahexaenoic acid supplementation of preterm infants and parent-reported symptoms of allergic disease at 7 years corrected age: follow-up of a randomized controlled trial.

BACKGROUND: Docosahexaenoic acid (DHA, 22:6n-3) supplementation in the prenatal period is associated with a reduction in the incidence of some symptoms of allergic disease. Infants born preterm are at increased risk of allergic disease, but it is unknown if DHA supplementation reduces the risk of childhood allergies. OBJECTIVES: The aim of this study was to determine if supplementation of infants born at <33 wk gestation with high-DHA compared with standard-DHA enteral feeds decreases the incidence and severity of parent-reported allergic disease symptoms at a corrected age (CA) of 7 y. METHODS: This study was a follow-up of an Australian multicenter randomized controlled trial. Infants were given high-DHA (∼1% total fatty acids) or standard-DHA (∼0.3% total fatty acids) enteral feeds from 2-4 d of postnatal age until 40 wk postmenstrual age. Parent-reported incidence of respiratory allergic disease symptoms including wheeze and rhinitis at 7 y CA were the main outcomes. Other outcomes included the incidence of eczema symptoms; severity of any symptoms; and the incidence of wheeze, rhinitis, rhinoconjunctivitis, and eczema from birth to 7 y CA. RESULTS: Data were available for 569 of 657 (87%) children originally randomized. Symptoms of wheeze or rhinitis at 7 y CA did not differ between high- and standard-DHA groups [wheeze: RR: 1.10; 95% CI: 0.73, 1.65; P = 0.66; rhinitis: RR: 1.09; 95% CI: 0.81, 1.46; P = 0.59]. There was no difference in other allergic disease symptoms at 7 y CA or in the severity of symptoms. Parent-reported symptoms of wheeze, rhinitis, rhinoconjunctivitis, or eczema from birth to 7 y CA did not differ between the groups. CONCLUSIONS: High-dose DHA supplementation of infants born at <33 wk gestation did not alter allergic disease symptoms or severity at 7 y CA, or from birth to 7 y CA compared with standard-dose DHA. This trial was registered with the Australian New Zealand Clinical Trials Registry as ANZCTR 12606000327583 (http://www.anzctr.org.au).

Enhancement of immune response mediated by oropharyngeal colostrum administration in preterm neonates.

BACKGROUND: The immune system of preterm infants is immature, being a significant cause of morbidity and mortality, particularly in the preterm infant. Oropharyngeal colostrum administration could be an immunomodulatory aid. Our aim was to evaluate the effect of oropharyngeal colostrum on the serum levels of immunoglobulins, lactoferrin, and resistin during the first month of life and to track the clinical outcome of the neonates. METHODS: One hundred preterm neonates born at <32 weeks of gestation and/or weighing < 1500 g and assisted in the Neonatal Intensive Care Unit were enrolled and divided into two groups: colostrum (n = 48) and control (n = 52). The subjects assigned to the colostrum group received 0.2 mL of colostrum (oropharyngeal route) every 4 hours for the first 15 days of life, and if mothers have inability to breastfeed, they were included in the control group (no oropharyngeal colostrum). Serum concentrations of IgA, IgM, and IgG1, lactoferrin, and resistin were assessed in both groups at 1, 3, 15, and 30 days of life. Clinical data during hospitalization were collected. RESULTS: IgA and IgM increased in preterm neonates who were administered colostrum for 15 and 30 days. Lactoferrin increased after 30 days, and resistin increased after 15 days of supplying oropharyngeal colostrum. The colostrum group underwent full enteral nutrition before, and no differences were observed in the common neonatal morbidities. CONCLUSION: Oropharyngeal colostrum administration is safe in preterm neonates and improves their immunologic profile, showing a potential role as an immunomodulatory agent.

Oropharyngeal colostrum in preventing mortality and morbidity in preterm infants.

BACKGROUND: Placing a small volume of colostrum directly onto the buccal mucosa of preterm infants during the early neonatal period may provide immunological and growth factors that stimulate the immune system and enhance intestinal growth. These benefits could potentially reduce the risk of infection and necrotising enterocolitis (NEC) and improve survival and long-term outcome. OBJECTIVES: To determine if early (within the first 48 hours of life) oropharyngeal administration of mother's own fresh or frozen/thawed colostrum can reduce rates of NEC, late-onset invasive infection, and/or mortality in preterm infants compared with controls. To assess trials for evidence of safety and harm (e.g. aspiration pneumonia). To compare effects of early oropharyngeal colostrum (OPC) versus no OPC, placebo, late OPC, and nasogastric colostrum. SEARCH METHODS: We used the standard search strategy of the Cochrane Neonatal Review Group to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 8), MEDLINE via PubMed (1966 to August 2017), Embase (1980 to August 2017), and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 to August 2017). We also searched clinical trials registries for ongoing and recently completed trials (clinicaltrials.gov; the World Health Organization International Trials Registry (www.whoint/ictrp/search/en/), and the ISRCTN Registry), conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. We performed the last search in August 2017. We contacted trial investigators regarding unpublished studies and data. SELECTION CRITERIA: We searched for published and unpublished randomised controlled trials comparing early administration of oropharyngeal colostrum (OPC) versus sham administration of water, oral formula, or donor breast milk, or versus no intervention. We also searched for studies comparing early OPC versus early nasogastric or nasojejunal administration of colostrum. We considered only trials that included preterm infants at < 37 weeks' gestation. We did not limit the review to any particular region or language. DATA COLLECTION AND ANALYSIS: Two review authors independently screened retrieved articles for inclusion and independently conducted data extraction, data analysis, and assessments of 'Risk of bias' and quality of evidence. We graded evidence quality using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. We contacted study authors for additional information or clarification when necessary. MAIN RESULTS: We included six studies that compared early oropharyngeal colostrum versus water, saline, placebo, or donor, or versus no intervention, enrolling 335 preterm infants with gestational ages ranging from 25 to 32 weeks' gestation and birth weights of 410 to 2500 grams. Researchers found no significant differences between OPC and control for primary outcomes - incidence of NEC (typical risk ratio (RR) 1.42, 95% confidence interval (CI) 0.50 to 4.02; six studies, 335 infants; P = 0.51; I² = 0%; very low-quality evidence), incidence of late-onset infection (typical RR 0.86, 95% CI 0.56 to 1.33; six studies, 335 infants; P = 0.50; I² = 0%; very low-quality evidence), and death before hospital discharge (typical RR 0.76, 95% CI 0.34 to 1.71; six studies, 335 infants; P = 0.51; I² = 0%; very low-quality evidence). Similarly, meta-analysis showed no difference in length of hospital stay between OPC and control groups (mean difference (MD) 0.81, 95% CI -5.87 to 7.5; four studies, 293 infants; P = 0.65; I² = 49%). Days to full enteral feeds were reduced in the OPC group with MD of -2.58 days (95% CI -4.01 to -1.14; six studies, 335 infants; P = 0.0004; I² = 28%; very low-quality evidence).The effect of OPC was uncertain because of small sample sizes and imprecision in study results (very low-quality evidence).No adverse effects were associated with OPC; however, data on adverse effects were insufficient, and no numerical data were available from the included studies.Overall the quality of included studies was low to very low across all outcomes. We downgraded GRADE outcomes because of concerns about allocation concealment and blinding, reporting bias, small sample sizes with few events, and wide confidence intervals. AUTHORS' CONCLUSIONS: Large, well-designed trials would be required to evaluate more precisely and reliably the effects of oropharyngeal colostrum on important outcomes for preterm infants.

Facilitating Colostrum Collection by Hospitalized Women in the Early Postpartum Period for Infant Trophic Feeding and Oral Immune Therapy.

Administration of colostrum for early trophic feedings and colostrum oral immune therapy for neonates in the NICU is essential to enhance gut maturation and lower risk of infections. However, it is often difficult for women to collect early colostrum because of its thick viscosity and low volume. Women may be unable to sit upright during pumping sessions because of postsurgical pain, acute or chronic illness, or birth complications and may need assistance. In this article, we describe specific techniques that providers can use to help women to collect colostrum when they are unable to accomplish collection on their own. Helping women collect and administer colostrum to their neonates in the NICU may engage and motivate them to continue to pump and provide breast milk for their hospitalized neonates.

Preterm Life in Sterile Conditions: A Study on Preterm, Germ-Free Piglets.

Preterm infants born with immature organ systems, which can impede normal development, can also be highly sensitive to different biological and/or environmental factors. Animal models could aid in investigating and understanding the effects of different conditions on the health of these immunocompromised infants. The epitheliochorial placentation of the pig prevents the prenatal transfer of protective colostral immunoglobulins. Surgical colostrum-deprived piglets are free of maternal immunoglobulins, and the cells that are normally provided via colostrum. We bred preterm germ-free piglets in sterile conditions and compared them with their term counterparts. Enterocyte development and intestinal morphology, tight junction proteins claudin-1 and occludin, pattern-recognizing receptors, adaptor molecules and coreceptors (RAGE, TLR2, TLR4, TLR9, MyD88, TRIF, MD2, and CD14), and inflammasome NLRP3 transcription were all evaluated. The production of inflammatory mediators IFN-α, IL-4, IL-6, IL-8, IL-10, IL-12/23 p40, TNF-α, IFN-γ, and high mobility group box 1 (HMGB1) in the intestine of germ-free piglets was also assessed. In the preterm germ-free piglets, the ileum showed decreased lamina propria cellularity, reduced villous height, and thinner and less distinct stratification - especially muscle layer, in comparison with their term counterparts. Claudin-1 transcription increased in the intestine of the preterm piglets. The transcription levels of pattern-recognizing receptors and adaptor molecules showed ambiguous trends between the groups. The levels of IL-6, IL-8, IL-10, and TNF-α were increased in the preterm ileum numerically (though not significantly), with statistically significant increases in the colon. Additionally, IL-12/23 p40 and IFN-γ were statistically significantly higher in the preterm colon. Both blood plasma and intestinal HMGB1 levels were nonsignificantly higher in the preterm group. We propose that the intestine of the preterm germ-free piglets showed "mild inflammation in sterile conditions." This model, which establishes preterm, hysterectomy-derived germ-free piglets, without protective maternal immunoglobulins, can be used to study influences of microbiota, nutrition, and therapeutic interventions on the development and health of vulnerable immunocompromised preterm infants.

Oropharyngeal Colostrum Administration in Very Low Birth Weight Infants: A Randomized Controlled Trial.

OBJECTIVES: Studies have confirmed the safety of oropharyngeal administration of colostrum in very low birth weight infants. However, the effect of oropharyngeal administration of colostrum on immune system is inconclusive. This study aims to evaluate the effect of oropharyngeal administration of colostrum on secretory immunoglobulin A and lactoferrin in very low birth weight infants. DESIGN: Randomized controlled trial. SETTING: Forty-bedded neonatal ICU in a university children's hospital in the People's Republic of China. PATIENTS: Very low birth weight infants were allocated to the study group (n = 32) and control group (n = 32). INTERVENTION: The intervention was oropharyngeal administration of 0.2 mL of their mother's colostrum every 4 hours for 7 days. The control group received saline solution. MEASUREMENTS AND MAIN RESULTS: Secretory immunoglobulin A and lactoferrin in urine and saliva were measured within 24 hours of life (baseline) and at 7 and 21 days. Primary outcomes were changes of secretory immunoglobulin A and lactoferrin in urine and saliva between baseline and at 7 and 21 days. Infant's clinical data were also collected during hospitalization. Change from baseline in lactoferrin in saliva at 7 days (5.18 ± 7.07 vs -1.74 ± 4.67 µg/mL; p < 0.001) and 21 days (5.31 ± 9.74 vs -1.17 ± 10.38 µg/mL; p = 0.02) shows statistic difference. No differences were found of lactoferrin in urine and also no differences of secretory immunoglobulin A in urine and saliva. There were also no differences between days to full enteral feeding, occurrence rate of clinical sepsis, proven sepsis, and necrotizing enterocolitis. CONCLUSIONS: Oropharyngeal administration of colostrum can increases the level of lactoferrin in saliva in very low birth weight infants. No effect could be documented of secretory immunoglobulin A and lactoferrin in urine. Larger trials are needed to better describe the benefit of oropharyngeal administration of colostrum, if any, in very low birth weight infants.

The pig as a model for premature infants - the importance of immunoglobulin supplementation for growth and development.

Preterm human neonates, contrary to preterm piglets, obtain immunoglobulins from their mothers via the placenta during intrauterine development. However, one should note that the majority of trans-placental transfer of immunoglobulins in humans takes place during the last trimester of pregnancy. It is also known that the feeding of limited amounts of colostrum or systemic infusion of small amounts of serum improves the survival of preterm and full-term piglets. Full-term piglets deprived of their mother's immunoglobulins exhibit strong apathy and develop watery diarrhoea, often resulting in death. The aim of the current study was to determine if provision of immunoglobulins using different approaches would be beneficial for survival outcomes. To reach the immunological sufficient level we infused immunoglobulins intravenously in amount mimicking the blood level in piglets fed with sow colostrum. Intravenous infusion of immunoglobulins in both preterm and full-term newborn piglets fully ensured their survival, growth and blood immunoglobulin G and protein levels similar to those observed in piglets fed colostrum. Piglets completely deprived of immunoglobulins exhibited significantly lower blood levels of immunoglobulins and protein compared to colostrum-fed animals. Piglets infused with only serum exhibited significantly lower blood immunoglobulin G level compared to those infused with immunoglobulins. In conclusion, based on the data obtained, we suggest that passive immune support provided by colostrum intake or early systemic infusion of Ig's in sufficient amounts is key to ensuring the general well-being of preterm and full-term new born piglets, used as an animal model for the human infant.

Oral colostrum priming shortens hospitalization without changing the immunomicrobial milieu.

OBJECTIVE: Oral colostrum priming (OCP) after birth in preterm infants is associated with improved weight gain and modification of the oral immunomicrobial environment. We hypothesized that OCP would modify salivary immune peptides and the oral microbiota in preterm infants. STUDY DESIGN: We conducted a prospective, randomized clinical trial to determine the effects of OCP on salivary immune peptide representation in preterm infants (<32 weeks completed gestation at birth). Saliva samples were collected before and after OCP. Salivary immune peptide representation was determined via mass spectroscopy. Oral microbiota representation was determined via sequencing of the 16S rRNA gene. RESULTS: Neonates who received OCP (n=48) had a 16-day reduction in the median length of hospitalization as compared with infants who did not receive OCP (n=51). No differences in salivary immune peptide sequence representation before OCP between groups were found. Longitudinal changes in peptides were detected (lysozyme C, immunoglobulin A, lactoferrin) but were limited to a single peptide difference (α-defensin 1) between primed and unprimed infants after OCP. We found no difference in microbial diversity between treatment groups at any time point, but diversity decreased significantly over time in both groups. OCP treatment marginally modified oral taxa with a decline in abundance of Streptococci in the OCP group at 30 days of life. CONCLUSIONS: OCP had neither an effect on the salivary peptides we examined nor on overall oral bacterial diversity and composition. Infants who received OCP had a reduced length of hospitalization and warrants further investigation.

Efectos de la administración de calostro orofaríngeo en recién nacidos prematuros sobre los niveles de inmunoglobulina A.

Introducción: el recién nacido prematuro de muy bajo peso (RNMBP) es inmunológicamente inmaduro y además presenta una alteración de las barreras naturales de defensa. Objetivo: evaluar los efectos que pueda tener la administración de calostro orofaríngeo, administrado durante los primeros 15 días posnatales, sobre los niveles de inmunoglobulina A (IgA) sérica en recién nacidos prematuros de muy bajo peso durante el primer mes de vida. Material y métodos: se desarrolló un estudio de intervención no aleatorizado con grupo control, en el que se incluyeron 38 recién nacidos con ≤ 32 + 6 semanas de gestación y/o menores de 1.500 g de peso. Los sujetos recibieron 0,2 ml de calostro de su madre cada 4 h, iniciándose el procedimiento en las primeras 24 h de vida hasta el 15.o día postnatal. Se midieron los niveles de IgA en la sangre al nacimiento, 3. er , 15.o y 30.o días de vida. Se registraron datos perinatales al nacimiento y durante el periodo de seguimiento. Resultados: IgA sérica aumentó de forma estadísticamente significativa en el grupo de intervención (M1 15,84 µg/ml, M2 20,07 µg/ml, M3 23,65 µg/ml, M4 30,34 µg/ml, p 0,001) y en el grupo control (M1 12,48 µg/ml, M2 16,48 µg/ml, p 0,018; M3 19,41 µg/ml, M4 22,48 µg/ml, p 0,001). Al mes de vida, los niveles de IgA sérica fueron significativamente mayores en el grupo de intervención que en el grupo control (p 0,026). Conclusiones: este estudio sugiere que la administración de calostro orofarínge.

Efectos de la administración de calostro orofaríngeo en recién nacidos prematuros sobre los niveles de inmunoglobulina A / Effect of oropharyngeal colostrum administration on immunoglobulin A levels in preterm newborns

Introducción: el recién nacido prematuro de muy bajo peso (RNMBP) es inmunológicamente inmaduro y además presenta una alteración de las barreras naturales de defensa. Objetivo: evaluar los efectos que pueda tener la administración de calostro orofaríngeo, administrado durante los primeros 15 días posnatales, sobre los niveles de inmunoglobulina A (IgA) sérica en recién nacidos prematuros de muy bajo peso durante el primer mes de vida. Material y métodos: se desarrolló un estudio de intervención no aleatorizado con grupo control, en el que se incluyeron 38 recién nacidos con ≤ 32 + 6 semanas de gestación y/o menores de 1.500 g de peso. Los sujetos recibieron 0,2 ml de calostro de su madre cada 4 h, iniciándose el procedimiento en las primeras 24 h de vida hasta el 15.º día postnatal. Se midieron los niveles de IgA en la sangre al nacimiento, 3.er, 15.º y 30.º días de vida. Se registraron datos perinatales al nacimiento y durante el periodo de seguimiento. Resultados: IgA sérica aumentó de forma estadísticamente significativa en el grupo de intervención (M1 15,84 µg/ml, M2 20,07 µg/ml, M3 23,65 µg/ml, M4 30,34 µg/ml, p 0,001) y en el grupo control (M1 12,48 µg/ml, M2 16,48 µg/ml, p 0,018; M3 19,41 µg/ml, M4 22,48 µg/ml, p 0,001). Al mes de vida, los niveles de IgA sérica fueron significativamente mayores en el grupo de intervención que en el grupo control (p 0,026). Conclusiones: este estudio sugiere que la administración de calostro orofaríngeo favorecería el desarrollo del sistema inmunológico de los recién nacidos prematuros y RNMBP a través del aumento de IgA al mes de vida (AU)

Introduction: Very low birth weight (VLBW) newborns have an immature immune system and also disrupted defense natural barriers. Objective: To evaluate the immunologic effects of oropharyngeal colostrum administration to VLBW infants in their first two weeks of life, by assessing IgA serum levels evolution up to one month of life. Material and methods: We conducted an interventional, no randomized, controlled trial recruiting 38 newborns under ≤ 32 + 6 gestational weeks and/or under 1,500 g at birth. Subjects received 0,2 ml of their mother colostrum every 4 hours, starting in the first 24 hours of life, and for a 15 days period. IgA serum levels were measured at birth, 3, 15 and 30 days of life. Perinatal data for the first month of life were registered. Results: Along the first month of life an increase in IgA levels was found in colostrum group (M1 15.84 µg/ml, M2 20.07 µg/ml, M3 23.65 µg ml, M4 30.34 µg/ml, p 0.001) and in control group (M1 12.48 µg/ml, M2 16.48 µg/ml, p 0.018; M3 19.41 µg/ml, M4 22.48 µg/ml, p 0.001). IgA serum levels were statistically increased in colostrum group, in respect to control group at one month of age (p 0.026). Conclusions: Our data suggest that oropharyngeal colostrum administration might facilitate the development of immune system in VLWB infants at one month of age, by increasing IgA serum levels (AU)

Prevention of Necrotizing Enterocolitis Through Manipulation of the Intestinal Microbiota of the Premature Infant.

PURPOSE: In spite of four decades of research, necrotizing enterocolitis (NEC) remains the most common gastrointestinal complication in premature infants with high mortality and long-term morbidity. The composition of the intestinal microbiota of the premature infant differs dramatically from that of the healthy term infant and appears to be an important risk factor for NEC. METHODS: We review the evidence of an association between intestinal dysbiosis and NEC and summarize published English language clinical trials and cohort studies involving attempts to manipulate the intestinal microbiota in premature infants. FINDINGS: Promising NEC prevention strategies that alter the intestinal microbiota include probiotics, prebiotics, synbiotics, lacteroferrin, and human milk feeding. IMPLICATIONS: Shaping the intestinal microbiota of the premature infant through human milk feeding and dietary supplements decreases the risk of NEC. Further studies to identify the ideal microbial composition and the most effective combination of supplements are indicated.

Leukocyte Populations in Human Preterm and Term Breast Milk Identified by Multicolour Flow Cytometry.

BACKGROUND: Extremely preterm infants are highly susceptible to bacterial infections but breast milk provides some protection. It is unknown if leukocyte numbers and subsets in milk differ between term and preterm breast milk. This study serially characterised leukocyte populations in breast milk of mothers of preterm and term infants using multicolour flow cytometry methods for extended differential leukocyte counts in blood. METHODS: Sixty mothers of extremely preterm (<28 weeks gestational age), very preterm (28-31 wk), and moderately preterm (32-36 wk), as well as term (37-41 wk) infants were recruited. Colostrum (d2-5), transitional (d8-12) and mature milk (d26-30) samples were collected, cells isolated, and leukocyte subsets analysed using flow cytometry. RESULTS: The major CD45+ leukocyte populations circulating in blood were also detectable in breast milk but at different frequencies. Progression of lactation was associated with decreasing CD45+ leukocyte concentration, as well as increases in the relative frequencies of neutrophils and immature granulocytes, and decreases in the relative frequencies of eosinophils, myeloid and B cell precursors, and CD16- monocytes. No differences were observed between preterm and term breast milk in leukocyte concentration, though minor differences between preterm groups in some leukocyte frequencies were observed. CONCLUSIONS: Flow cytometry is a useful tool to identify and quantify leukocyte subsets in breast milk. The stage of lactation is associated with major changes in milk leukocyte composition in this population. Fresh preterm breast milk is not deficient in leukocytes, but shorter gestation may be associated with minor differences in leukocyte subset frequencies in preterm compared to term breast milk.

Arginine depletion increases susceptibility to serious infections in preterm newborns.

Preterm newborns are highly susceptible to bacterial infections. This susceptibility is regarded as being due to immaturity of multiple pathways of the immune system. However, it is unclear whether a mechanism that unifies these different, suppressed pathways exists. Here, we argue that the immune vulnerability of the preterm neonate is critically related to arginine depletion. Arginine, a "conditionally essential" amino acid, is depleted in acute catabolic states, including sepsis. Its metabolism is highly compartmentalized and regulated, including by arginase-mediated hydrolysis. Recent data suggest that arginase II-mediated arginine depletion is essential for the innate immune suppression that occurs in newborn models of bacterial challenge, impairing pathways critical for the immune response. Evidence that arginine depletion mediates protection from immune activation during first gut colonization suggests a regulatory role in controlling gut-derived pathogens. Clinical studies show that plasma arginine is depleted during sepsis. In keeping with animal studies, small clinical trials of L-arginine supplementation have shown benefit in reducing necrotizing enterocolitis in premature neonates. We propose a novel, broader hypothesis that arginine depletion during bacterial challenge is a key factor limiting the neonate's ability to mount an adequate immune response, contributing to the increased susceptibility to infections, particularly with respect to gut-derived sepsis.

Small intestinal intraepithelial TCRγδ+ T lymphocytes are present in the premature intestine but selectively reduced in surgical necrotizing enterocolitis.

BACKGROUND: Gastrointestinal barrier immaturity predisposes preterm infants to necrotizing enterocolitis (NEC). Intraepithelial lymphocytes (IEL) bearing the unconventional T cell receptor (TCR) γδ (γδ IEL) maintain intestinal integrity and prevent bacterial translocation in part through production of interleukin (IL) 17. OBJECTIVE: We sought to study the development of γδ IEL in the ileum of human infants and examine their role in NEC pathogenesis. We defined the ontogeny of γδ IEL proportions in murine and human intestine and subjected tcrδ-/- mice to experimental gut injury. In addition, we used polychromatic flow cytometry to calculate percentages of viable IEL (defined as CD3+ CD8+ CD103+ lymphocytes) and the fraction of γδ IEL in surgically resected tissue from infants with NEC and gestational age matched non-NEC surgical controls. RESULTS: In human preterm infants, the proportion of IEL was reduced by 66% in 11 NEC ileum resections compared to 30 non-NEC controls (p<0.001). While γδ IEL dominated over conventional αß IEL early in gestation in mice and in humans, γδ IEL were preferential decreased in the ileum of surgical NEC patients compared to non-NEC controls (50% reduction, p<0.05). Loss of IEL in human NEC was associated with downregulation of the Th17 transcription factor retinoic acid-related orphan nuclear hormone receptor C (RORC, p<0.001). TCRδ-deficient mice showed increased severity of experimental gut injury (p<0.05) with higher TNFα expression but downregulation of IL17A. CONCLUSION: Complimentary mouse and human data suggest a role of γδ IEL in IL17 production and intestinal barrier production early in life. Specific loss of the γδ IEL fraction may contribute to NEC pathogenesis. Nutritional or pharmacological interventions to support γδ IEL maintenance in the developing small intestine could serve as novel strategies for NEC prevention.

Neutral and acidic oligosaccharides supplementation does not increase the vaccine antibody response in preterm infants in a randomized clinical trial.

BACKGROUND: In preterm infants, a decreased immunological response and lower serological effectiveness are observed after immunizations due to ineffectiveness of both humoral and cellular immune mechanisms. OBJECTIVE: To determine the effect of 80% neutral oligosaccharides [small-chain galacto-oligosaccharides/long-chain fructo-oligosaccharides (scGOS/lcFOS)] in combination with 20% pectin-derived acidic oligosaccharides (pAOS) on antibody concentrations after DTaP-IPV-Hib immunization in preterm infants. DESIGN: In this randomized clinical trial, preterm infants with gestational age <32 weeks and/or birth weight <1500 g received enteral supplementation with scGOS/lcFOS/pAOS or placebo (maltodextrin) between days 3 and 30 of life. Blood samples were collected at 5 and 12 months of age. RESULTS: In total, 113 infants were included. Baseline and nutritional characteristics were not different in both groups. Geometric mean titers were not different after prebiotic supplementation at 5 months, Ptx (37/44 EU/ml), FHA (78/96 EU/ml), Prn (78/80 EU/ml), Diphtheria (0.40/0.57 IU/ml), Tetanus (0.74/0.99 IU/ml) and Hib (0.35/0.63 µg/ml), and at 12 months Ptx (55/66 EU/ml), FHA (122/119 EU/ml), Prn (116/106 Eu/ml), Diphtheria (0.88/1.11 IU/ml), Tetanus (1.64/1.79 IU/ml) and Hib (2.91/2.55 µg/ml). CONCLUSIONS: Enteral supplementation of neutral (scGOS/lcFOS) and acidic oligosaccharides (pAOS) does not improve the immunization response in preterm infants. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN16211826 ISRCTN16211826.