Dojčenie a nekrotizujúca enterokolitída nedonosencov

Klinické štúdie sa zhodujú v tom, že kŕmenie nedonosených novorodencov materským mliekom ich účinne chráni pred rozvojom nekrotizujúcej enterokolitídy (ťažké zápalové ochorenie čreva typické pre závažne nezrelé deti, jedna z najčastejších príčin úmrtnosti v tejto hmotnostnej kategórii). Materské mlieko podporuje kolonizáciu gastrointestinálneho (zažívacieho) traktu nedonosencov prirodzenou bakteriálnou flórou, zatiaľčo v črevách detí kŕmených detí prevládajú potenciálne nebezpečné bakteriálne kmene. Prirodzené zložky materského mlieka (oligosacharidy a glykokonjugáty) zabraňujú prichyteniu nebezpečných patogénov (choroboplodných zárodkov) na črevnú stenu. Materské mlieko okrem toho obsahuje gastrointestinálne rastové faktory, ktoré výrazným spôsobom ovplyvňujú dozrievanie nezrelej črevnej sliznice u nedonosencov a tým aj jej funkcieschopnosť.

Feeding strategies for premature infants: beneficial outcomes of feeding fortified human milk versus preterm formula. 
Schanler RJ, Shulman RJ, Lau C 
Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA. schanler@bcm.tmc.edu
BACKGROUND: In a large-scale study of feeding strategies in premature infants (early vs later initiation of enteral feeding, continuous vs bolus tube-feeding, and human milk vs formula), the feeding of human milk had more effect on the outcomes measured than any other strategy studied. Therefore, this report describes the growth, nutritional status, feeding tolerance, and health of participating premature infants who were fed fortified human milk (FHM) in comparison with those who were fed exclusively preterm formula (PF). METHODS: Premature infants were assigned randomly in a balanced two-way design to early (gastrointestinal priming for 10 days) versus late initiation of feeding (total parenteral nutrition only) and continuous infusion versus intermittent bolus tube-feeding groups. The type of milk was determined by parental choice and infants to receive their mother's milk were randomized separately from those to receive formula. The duration of the study spanned the entire hospitalization of the infant. To evaluate human milk versus formula feeding, we compared outcomes of infants fed >50 mL. kg-1. day-1 of any human milk (averaged throughout the hospitalization) with those of infants fed exclusively PF. Growth, feeding tolerance, and health status were measured daily. Serum indices of nutritional status were measured serially, and 72-hour nutrient balance studies were conducted at 6 and 9 weeks postnatally. RESULTS: A total of 108 infants were fed either >50 mL. kg-1. day-1 human milk (FHM, n = 62) or exclusively PF (n = 46). Gestational age (28 +/- 1 weeks each), birth weight (1.07 +/- 0.17 vs 1.04 +/- 0.19 kg), birth length and head circumference, and distribution among feeding strategies were similar between groups. Infants fed FHM were discharged earlier (73 +/- 19 vs 88 +/- 47 days) despite significantly slower rates of weight gain (22 +/- 7 vs 26 +/- 6 g. kg-1. day-1), length increment (0.8 +/- 0.3 vs 1.0 +/- 0.3 cm. week-1), and increment in the sum of five skinfold measurements (0.86 +/- 0.40 vs 1.23 +/- 0.42 mm. week-1) than infants fed PF. The incidence of necrotizing enterocolitis and late-onset sepsis was less in the FHM group. Overall, there were no differences in any measure of feeding tolerance between groups. Milk intakes of infants fed FHM were significantly greater than those fed PF (180 +/- 13 vs 157 +/- 10 mL. kg-1. day-1). The intakes of nitrogen and copper were higher and magnesium and zinc were lower in group FHM versus PF. Fat and energy absorption were lower and phosphorus, zinc, and copper absorption were higher in group FHM versus PF. The postnatal retention (balance) surpassed the intrauterine accretion rate of nitrogen, phosphorus, magnesium, zinc, and copper in the FHM group, and of nitrogen, magnesium, and copper in the PF group. CONCLUSIONS: Although the study does not allow a comparison of FHM with unfortified human milk, the data suggest that the unique properties of human milk promote an improved host defense and gastrointestinal function compared with the feeding of formula. The benefits of improved health (less sepsis and necrotizing enterocolitis) associated with the feeding of FHM outweighed the slower rate of growth observed, suggesting that the feeding of FHM should be promoted actively in premature infants.

Necrotizing enterocolitis after gastroschisis repair: a preventable complication? 
Jayanthi S, Seymour P, Puntis JW, Stringer MD 
Department of Paediatric Surgery and Neonatology, Leeds General Infirmary, England.
BACKGROUND: Necrotizing enterocolitis (NEC) has been documented in up to 20% of infants after repair of gastroschisis and is responsible for significant morbidity. NEC is reported to occur up to 10 times more in preterm infants receiving standard formula compared with those who have been fed exclusively with breast milk. Does breast milk confer a similar protection against NEC in infants who have undergone surgery for gastroschisis? METHODS: All newborns with gastroschisis delivered between 1990 and 1996 and treated in a single neonatal unit were analyzed retrospectively. Clinical data, details of feeding regimens, and episodes of definite NEC were recorded. RESULTS: Of 60 infants with gastroschisis, 6 (10%) died but none had evidence of NEC. Of the remaining 54 infants, clinical and radiological signs of NEC developed in 8 (15%). All recovered with medical treatment including the three patients with recurrent episodes. NEC developed in none of the 12 babies exclusively fed with expressed breast milk (EBM) in contrast to 1 (5%) of the 19 who received both EBM and formula, and 7 (30%) of the 23 who were fed solely on formula. There was no significant difference in gestation, incidence of primary versus silo closure, or incidence of intestinal atresia/stenosis in those with NEC (n=8) compared with those without (n=46), but birth weight in the NEC group was lower. NEC was less likely to develop in infants who received EBM than those who were exclusively formula fed (P < .02). CONCLUSION: After gastroschisis repair, feeding with maternal expressed breast milk may help to protect the infant from developing NEC.

Role of bacterial colonization in neonatal necrotizing enterocolitis and its prevention. 
Dai D, Walker WA 
Shanghai Institute for Pediatric Research, Shanghai Second Medical University, China.
Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency in premature infants. A major component of the pathophysiology of NEC is the nature of the interaction of bacteria with the premature gut. Intestine microflora are important to the host in resistance to bacterial infections. Diet and environmental conditions can influence this ecosystem. A breast-fed full-term infant has a preferred intestine microbiota in which bifidobacteria predominate over the potentially harmful bacteria, whereas in formula-fed infants coliforms, enterococci and bacteroides predominate. The pattern of bacterial colonization in the premature neonate gut is quite different from that in the gut of the healthy full-term infant. Those infants requiring intensive care acquire intestinal organisms slowly, and the establishment of bifidobacterial flora is retarded. A delayed bacterial colonization of the gut with a limited number of bacterial species tends to be virulent. Bacterial overgrowth is one of major factors promoting bacterial translocation. The aberrant colonization of the premature infant may contribute to the development of NEC.Breast feeding protects infants against NEC. Oligosaccharides and glycoconjugates, natural components in human milk, may prevent intestinal attachment of enteropathogens by acting as receptor homologues. Probiotics and prebiotics modulate the composition of human intestine microflora to the benefit of the host. The beneficial effects may result in the suppression of colonization of harmful microoganisms and/or the stimulation of bifidobacterial growth. In the future, control and manipulation of bacterial colonization in the neonate gut may be a new approach to the prevention and treatment of bacterial intestinal disease of various etiologies.

Human milk and host defence: immediate and long-term effects. 
Hanson LA 
Department of Clinical Immunology, Goteborg University, Sweden. lars.a.hanson@immuno.gu.se
Convincing studies demonstrate significant protection during breastfeeding against diarrhoea, respiratory tract infections, otitis media, bacteraemia, bacterial meningitis, botulism, urinary tract infections and necrotizing enterocolitis. There is also good evidence for enhanced protection for years after the termination of breastfeeding against Haemophilus influenzae type b infections, otitis media, diarrhoea, respiratory tract infections and wheezing bronchitis. In some reports breastfeeding has also improved vaccine responses. Several studies show that milk may actively stimulate the immune system of the offspring via transfer of anti-idiotypic antibodies and lymphocytes. This may explain why breastfeeding diminishes the risk of developing coeliac disease. Some investigations suggest that there may also be a similar effect on allergic diseases and autoimmune diseases, as well as inflammatory bowel diseases and certain tumours. This needs to be confirmed.

Effects of nutrients in human milk on the recipient premature infant. 
Schanler RJ, Atkinson SA 
Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030-2600, USA. schanler@bcm.tmc.edu
As the rate of survival of premature infants is increasing, more attention is necessarily focused on improving the quality of survival through optimal nutritional management. The nutritional needs of the premature infant are greater than at any other time in the life cycle. The benefits of human milk for term infants are well known. Emerging data suggest that human milk may especially benefit the premature infant. The human milk-fed premature infant may experience improved health (such as lower rates of infection and necrotizing enterocolitis), gastrointestinal function, and neurodevelopment. These factors may outweigh the concerns about adequate growth, nutrient accretion, and biochemical indices of nutritional status attributed to the lower nutrient content of human milk compared with preterm formula. Some of the nutritional concerns may be met by the use of multinutrient supplements during the time infants receive tube-feeding, generally the time prior to attaining complete oral feeding in-hospital. The available data suggest that the quality of survival of premature infants can be improved, both in the short-term and long-term, through the feeding of human milk.

Trophic factors for the gastrointestinal tract. 
Carver JD, Barness LA 
Department of Pediatrics, University of South Florida College of Medicine, Tampa, USA.
GI trophic factors that influence the coordinated pre- and postnatal growth and development of the GI tract have been identified. Studies in animals and humans demonstrate that GI trophic factors can initiate cellular growth and expression of differentiated function, and they are important in adaptation and repair following injury. Systemically as well as enterally administered growth factors can stimulate GI growth and maturation, suggesting that trophic factors in the serum of neonates may modulate GI growth via receptors on the serosal membranes of enterocytes. GI trophic factors may be synthesized endogenously or provided postnatally in milk. GI trophic factors in human milk play an important role in regulating the adaptive functional changes that accompany the transition to postnatal enteral feedings. Although human milk growth factors do not appear to be essential for infant survival, the elevated risk of gastrointestinal-related illnesses in formula-fed as compared with breast-fed infants (diarrhea, necrotizing enterocolitis, colitis, Crohn's disease) suggest that bioactive compounds in human milk contribute to the apparent protective effect of breast feeding. GI trophic factors have the potential to be used therapeutically to enhance GI maturation and repair following injury. These applications may be particularly useful in the premature or postsurgical infant. Several issues require further research, including (1) the mechanism of action, (2) the efficacy of oral versus systemic administration, (3) characterization of the complex interactions between the various growth factors, because some appear to act synergistically, (4) the effect of exogenously administered growth factors on endogenous production of that factor, its receptor, or other growth factors, (5) the effect of growth factors upon tissues not directly associated with the GI tract, and (6) the determination of safe and effective upper limits.

 Protective nutrients and bacterial colonization in the immature human gut. 
Dai D, Walker WA 
Shanghai Institute for Pediatric Research, Shanghai Second Medical University, China.

The normal human microflora is a complex ecosystem that is in part dependent on enteric nutrients for establishing colonization. The gut microbiota are important to the host with regard to metabolic functions and resistance to bacterial infections. At birth, bacterial colonization of a previously germ-free human gut begins. Diet and environmental conditions can influence this ecosystem. A breast-fed, full-term infant has a preferred intestine microbiota in which bifidobacteria predominate over potentially harmful bacteria, whereas in formula-fed infants, coliforms, enterococci, and bacteroides predominate. The pattern of bacterial colonization in the premature neonatal gut is different from that in the healthy, full-term infant gut. Those infants requiring intensive care acquire intestinal organisms slowly, and the establishment of bifidobacterial flora is retarded. A delayed bacterial colonization of the gut with a limited number of bacterial species tends to be virulent. Bacterial overgrowth is one of the major factors that promote bacterial translocation. The aberrant colonization of the premature infant may contribute to the development of necrotizing enterocolitis. Breast-feeding protects infants against infection. Oligo-saccharides and glycoconjugates, natural components in human milk, may prevent intestinal attachment of enteropathogens by acting as receptor homologues. Probiotics and prebiotics modulate the composition of the human intestinal microflora to the benefit of the host. These beneficial effects may result in the suppression of harmful microorganisms, the stimulation of bifidobacterial growth, or both. In the future, control and manipulation of the bacterial colonization in the neonatal gut may be a new approach to the prevention and treatment of intestinal infectious diseases of various etiologies.