Granulocyte colony-stimulating factor is present in human milk and its receptor is present in human fetal intestine

Evolutionary bridges: how factors present in amniotic fluid and human milk help mature the gut

Necrotizing enterocolitis (NEC) continues to be a leading cause of morbidity and mortality in preterm infants. As modern medicine significantly improves the survival of extremely premature infants, the persistence of NEC underscores our limited understanding of its pathogenesis. Due to early delivery, a preterm infant's exposure to amniotic fluid (AF) is abruptly truncated. Replete with bioactive molecules, AF plays an important role in fetal intestinal maturation and preparation for contact with the environment, thus its absence during development of the intestine may contribute to increased susceptibility to NEC. Human milk (HM), particularly during the initial phases of lactation, is a cornerstone of neonatal intestinal defense. The concentrations and activities of several bioactive factors in HM parallel those of AF, suggesting continuity of protection. In this review, we discuss the predominant overlapping bioactive components of HM and AF, with an emphasis on those associated with intestinal growth or reduction of NEC.

Breastfeeding and the developmental origins of mucosal immunity: how human milk shapes the innate and adaptive mucosal immune systems

PURPOSE OF REVIEW

Breastfeeding provides passive immunity while the neonatal immune system matures, and may also protect against chronic immune-mediated conditions long after weaning. This review summarizes current knowledge and new discoveries about human milk and mucosal immunity.

RECENT FINDINGS

New data suggest that certain microbes in maternal milk may seed and shape the infant gut microbiota, which play a key role in regulating gut barrier integrity and training the developing immune system. Human milk oligosaccharides, best known for their prebiotic functions, have now been shown to directly modulate gene expression in mast and goblet cells in the gastrointestinal tract. Epidemiologic data show a reduced risk of peanut sensitization among infants breastfed by peanut-consuming mothers, suggesting a role for milk-borne food antigens in tolerance development. Cross-fostering experiments in mice suggest the soluble Toll-like receptor 2, found in human milk, may be critical in this process. Finally, interest in human milk antibodies surged during the pandemic with the identification of neutralizing severe acute respiratory syndrome coronavirus 2 antibodies in maternal milk following both natural infection and vaccination.

SUMMARY

Human milk provides critical immune protection and stimulation to breastfed infants. Understanding the underlying mechanisms could identify new therapeutic targets and strategies for disease prevention across the lifespan.

Human Milk Growth Factors and Their Role in NEC Prevention: A Narrative Review

Growing evidence demonstrates human milk's protective effect against necrotizing enterocolitis (NEC). Human milk derives these properties from biologically active compounds that influence intestinal growth, barrier function, microvascular development, and immunological maturation. Among these protective compounds are growth factors that are secreted into milk with relatively high concentrations during the early postnatal period, when newborns are most susceptible to NEC. This paper reviews the current knowledge on human milk growth factors and their mechanisms of action relevant to NEC prevention. It will also discuss the stability of these growth factors with human milk pasteurization and their potential for use as supplements to infant formulas with the goal of preventing NEC.

Milk fat globule membrane in infant nutrition: a dairy industry perspective

This review provides an overview of the composition, structure, and biological activities of milk fat globule membrane (MFGM) compounds with focus on the future application of this compound as a food ingredient. MFGM is a particular component of mammalian milks and is comprised of a tri-layer of polar lipids, glycolipids and proteins. In recent years, MFGM has been extensively studied for the purpose of enhancing the efficacy of infant nutrition formula. For example, infant formulas supplemented with bovine MFGM have shown promising results with regard to neurodevelopment and defense against infections. Components of MFGM have been shown to present several health benefits as the proteins of the membrane have shown antiviral activity and a reduction in the incidence of diarrhea. Moreover, the presence of sphingomyelin, a phospholipid, implies beneficial effects on human health such as enhanced neuronal development in infants and the protection of neonates from bacterial infections. The development of a lipid that is similar to human milk fat would represent a significant advance for the infant formula industry and would offer high technology formulas for those infants that depend on infant formula. The complexity of the structure of MFGM and its nutritional and technological properties is critically examined in this review with a focus on issues relevant to the dairy industry.

The Function and Alteration of Immunological Properties in Human Milk of Obese Mothers

Maternal obesity is associated with metabolic changes in mothers and higher risk of obesity in the offspring. Obesity in breastfeeding mothers appears to influence human milk production as well as the quality of human milk. Maternal obesity is associated with alteration of immunological factors concentrations in the human milk, such as C-reactive protein (CRP), leptin, IL-6, insulin, TNF-Alpha, ghrelin, adiponectin, and obestatin. Human milk is considered a first choice for infant nutrition due to the complete profile of macro nutrients, micro nutrients, and immunological properties. It is essential to understand how maternal obesity influences immunological properties of human milk because alterations could impact the nutrition status and health of the infant. This review summarizes the literature regarding the impact of maternal obesity on the concentration of particular immunological properties in the human milk.

Cytokines and Soluble Receptors in Breast Milk as Enhancers of Oral Tolerance Development

The postpartum period is an important window during which environmental factors can shape the life-long health of the infant. This time period often coincides with substantial milk consumption either in the form of breast milk or from cow's milk sources, such as infant formulas. Although breast milk is the most beneficial source of nutrients for infants during the first 6 months after birth, its role in regulating food allergy development, through regulation of oral tolerance, is still controversial. Breast milk contains several factors that can impact mucosal immune function, including immune cells, antibodies, microbiota, oligosaccharides, cytokines, and soluble receptors. However, there is considerable variation in the assessed levels of cytokines and soluble receptors between studies and across the lactation period. Most of these cytokines and soluble receptors are absent, or only found in limited quantities, in commercial baby formulas. Differences in content of these pluripotent factors, which impact on both the mother and the neonate, could contribute to the controversy surrounding the role of breast milk regulating oral tolerance. This review highlights current knowledge about the importance of cytokines and soluble receptors in breast milk on the development of oral tolerance and tolerance-relateddisorders. Understanding the mechanisms by which such milk components might promote oral tolerance could aid in the development of improved strategies for allergy prevention.

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.

Protective Role of Passively Transferred Maternal Cytokines against Bordetella pertussis Infection in Newborn Piglets

Maternal vaccination represents a potential strategy to protect both the mother and the offspring against life-threatening infections. This protective role has mainly been associated with antibodies, but the role of cell-mediated immunity, in particular passively transferred cytokines, is not well understood. Here, using a pertussis model, we have demonstrated that immunization of pregnant sows with heat-inactivated bacteria leads to induction of a wide range of cytokines (e.g., tumor necrosis factor alpha [TNF-α], gamma interferon [IFN-γ], interleukin-6 [IL-6], IL-8, and IL-12/IL-23p40) in addition to pertussis-specific antibodies. These cytokines can be detected in the sera and colostrum/milk of vaccinated sows and subsequently were detected at significant levels in the serum and bronchoalveolar lavage fluid of piglets born to vaccinated sows together with pertussis-specific antibodies. In contrast, active vaccination of newborn piglets with heat-inactivated bacteria induced high levels of specific IgG and IgA but no cytokines. Although the levels of antibodies in vaccinated piglets were comparable to those of passively transferred antibodies, no protection against Bordetella pertussis infection was observed. Thus, our results demonstrate that a combination of passively transferred cytokines and antibodies is crucial for disease protection. The presence of passively transferred cytokines/antibodies influences the cytokine secretion ability of splenocytes in the neonate, which provides novel evidence that maternal immunization can influence the newborn's cytokine milieu and may impact immune cell differentiation (e.g., Th1/Th2 phenotype). Therefore, these maternally derived cytokines may play an essential role both as mediators of early defense against infections and possibly as modulators of the immune repertoire of the offspring.

The Importance of Human Milk for Immunity in Preterm Infants

The immune system of preterm infants is immature, placing them at increased risk for serious immune-related complications. Human milk provides a variety of immune protective and immune maturation factors that are beneficial to the preterm infant's poorly developed immune system. The most studied immune components in human milk include antimicrobial proteins, maternal leukocytes, immunoglobulins, cytokines and chemokines, oligosaccharides, gangliosides, nucleotides, and long-chain polyunsaturated fatty acids. There is growing evidence that these components contribute to the lower incidence of immune-related conditions in the preterm infant. Therefore, provision of these components in human milk, donor milk, or formula may provide immunologic benefits.

G-CSF and Erythropoietin Stability in Amniotic Fluid during Simulated in vitro Digestion Conditions

Objective:

To determine the stability of granulocyte colony-stimulating factor (G-CSF) and erythropoietin (Epo) in human amniotic fluid and recombinant G-CSF (Neupogen) and Epo (Epogen) in simulated amniotic fluid to digestions at pH concentrations of 3.2, 4.5, and 5.8 to assess their bioavailability to the neonate.

Design:

A simulated amniotic fluid containing Neupogen and Epogen was subjected to in vitro conditions that mimicked preprandial and postprandial neonatal intestinal digestion. Human amniotic fluid was tested using identical digestion conditions as well as human amniotic fluid to which Epogen and Neupogen had been added.

Main Outcome Measures:

The percentages of G-CSF/Epo and Neupogen/Epogen remaining after 1 and 2 hours of simulated digestions were compared with those at time zero, and concentrations at 2 hours were compared with those at 1 hour and time zero.

Results:

In simulated amniotic fluid at pH 3.2, significant degradation of G-CSF was observed at 1 hour (p = 0.03). No differences were observed at 1 or 2 hours for either pH 4.5 (p = 0.30 and 0.11, respectively) or pH 5.8 (p = 0.20 and 0.49, respectively). Human amniotic fluid exhibited significant degradation pH 3.2 (p = 0.04) and pH 4.5 (p < 0.05) at 1 hour; no difference was noted at pH 5.8 at 1 hour (p = 0.34). When additional Neupogen was added to human amniotic fluid, significant degradation was observed at pH 3.2 (p < 0.05) and pH 4.5 (p = 0.03) at 1 hour; no difference was noted at 1 hour at pH 5.8 (p = 0.11). In simulated amniotic fluid at pH 3.2, significant degradation of Epo occurred at 1 hour (p < 0.05). There were no differences at 1 hour for pH 4.5 (p = 0.50) or pH 5.8 (p = 0.17). Human amniotic fluid exhibited significant degradation at pH 3.2 (p < 0.05) and pH 4.5 (p < 0.05) at 1 hour; no difference was noted at 1 hour at pH 5.8 (p = 0.34). When additional Epogen was added to human amniotic fluid, significant degradation was observed at pH 3.2 (p = 0.001) and pH 4.5 (p = 0.003); no difference was noted at 1 hour at pH 5.8 (p = 0.31).

Conclusions:

G-CSF/Epo in human amniotic fluid and Neupogen/Epogen in simulated amniotic fluid are preserved to varying degrees during simulated digestion conditions. The degree of degradation of both cytokines was time- and pH-dependent. Measurable quantities of G-CSF and Epo are biologically available when swallowed by the fetus or a preterm neonate.

Importance of Amniotic Fluid in Gastrointestinal Development

Amniotic fluid (AF) is a bioactive medium containing various trophic factors and other nutrients that are necessary for fetal growth and organogenesis. Many trophic factors present in AF are responsible for the development of the fetal gastrointestinal tract. Development and maturation of the gastrointestinal tract is a complex cascade that begins before birth and continues during infancy and childhood by breastfeeding. Many factors, such as genetic preprogramming, local and systemic endocrine secretions, and many trophic factors from swallowed AF, modulate the development and growth of the gastrointestinal tract. Studies are currently examining a potential role of stem cells in AF as a protective agent against the development of necrotizing enterocolitis in preterm infants. Preliminary studies suggest that simulated AF may be a possible means of reducing feeding intolerance. In this article, the authors review the various functions of AF and its importance in fetal gastrointestinal tract development. They also examine possible future uses of this extremely important bioactive fluid.

Amniotic fluid: Source of trophic factors for the developing intestine

The gastrointestinal tract (GIT) is a complex system, which changes in response to requirements of the body. GIT represents a barrier to the external environment. To achieve this, epithelial cells must renew rapidly. This renewal of epithelial cells starts in the fetal life under the influence of many GIT peptides by swallowing amniotic fluid (AF). Development and maturation of GIT is a very complex cascade that begins long before birth and continues during infancy and childhood by breast-feeding. Many factors like genetic preprogramming, local and systemic endocrine secretions and many trophic factors (TF) from swallowed AF contribute and modulate the development and growth of the GIT. GIT morphogenesis, differentiation and functional development depend on the activity of various TF in the AF. This manuscript will review the role of AF borne TF in the development of GIT.

Enteral granulocyte-colony stimulating factor and erythropoietin early in life improves feeding tolerance in preterm infants: a randomized controlled trial

OBJECTIVE

To evaluate the efficacy and safety of enteral recombinant human granulocyte colony-stimulating factor (rhG-CSF) and recombinant human erythropoietin (rhEPO) in preventing feeding intolerance.

STUDY DESIGN

An interventional randomized control trial was conducted in 90 preterm infants born at ≤33 weeks gestational age. The neonates were assigned to 4 groups; 20 received rhG-CSF, 20 received rhEPO, 20 received both, and 30 received distilled water (placebo control). The test solution was given at the beginning of enteral feeding and was discontinued when enteral intake reached 100 mL/kg/day or after a maximum of 7 days, whichever came first. Feeding tolerance and adverse effects of treatment were assessed. Serum granulocyte colony-stimulating factor and erythropoietin levels were measured on days 0 and 7 of treatment.

RESULTS

All neonates tolerated the treatment without side effects. Neonates who received rhG-CSF and/or rhEPO had better feeding tolerance, as reflected by earlier achievement of 75 mL/kg/day, 100 mL/kg/day, and full enteral feeding of 150 mL/kg/day with earlier weight gain and a shorter hospital stay (P < .05). The risk of necrotizing enterocolitis was reduced from 10% to 0% in all treatment groups (P < .05). There was a shorter duration of withholding of feeding secondary to feeding intolerance among neonates receiving both rhG-CSF and rhEPO compared with those receiving placebo (P < .05). Serum levels of granulocyte colony-stimulating factor and erythropoietin at 0 and 7 days did not differ across the treatment groups.

CONCLUSIONS

Enteral administration of rhG-CSF and/or rhEPO improves feeding outcome and decreases the risk of necrotizing enterocolitis in preterm neonates. The mechanism may involve the prevention of villous atrophy.

Maternal surfactant protein A influences the immunoprotective properties of milk in a murine model

BACKGROUND

Maternal surfactant protein A (SP-A), a collectin with innate immune system function, is critical to newborn mouse survival preventing bacterial peritonitis associated with a nonhygienic environmental exposure. We hypothesized that SP-A improves newborn survival by optimizing milk immunoprotection.

METHODS

Regional (lung) and systemic (milk and serum) immunologic responses to a novel antigen, 2,4-dintirophenyl keyhole limpet hemocyanin (DNP-KLH), and to a nonhygienic environment were evaluated in wild-type (WT) and SP-A null murine dams. Cross-fostering pups assessed the impact of milk on newborn survival.

RESULTS

Maternal SP-A optimized antigen-specific milk secretory IgA (sIgA) production following the DNP-KLH exposure. Milk total and environment-specific sIgA production was not dependent on maternal SP-A in the nonhygienic exposure. At baseline, SP-A null milk contained physiologically meaningful increases in two proinflammatory cytokines compared with WT milk. The lack of SP-A plus the nonhygienic environmental exposure synergistically increased the number of proinflammatory cytokines contained in milk. Finally, the SP-A null genotype decreased pup survival during a nonhygienic environmental exposure.

CONCLUSION

Maternal SP-A impacts milk sIgA and cytokine content, and is associated with improved newborn health.

Chemotherapy, targeted agents, antiemetics and growth-factors in human milk: how should we counsel cancer patients about breastfeeding?

An increasing number of women are diagnosed with cancer during pregnancy and lactation. Women are usually advised to interrupt breastfeeding during systemic anticancer treatment for fear of serious adverse effects to the nursed infant. However, the issue is poorly addressed in the literature and very few studies have evaluated the safety of breastfeeding during or after cytotoxic drugs or target agents administration. In this review we will analyze the available evidence that addresses the issue of anticancer drugs, targeted agents, antiemetics and growth-factors excretion in human milk. This could serve as a unique resource that may aid physicians in the management of breastfeeding cancer patients interested in maintaining lactation during treatment.

The role of growth factors in intestinal regeneration and repair in necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a devastating intestinal disease resulting in major neonatal morbidity and mortality. The pathology is poorly understood, and the means of preventing and treating NEC are limited. Several endogenous growth factors have been identified as having important roles in intestinal growth as well as aiding intestinal repair from injury or inflammation. In this review, we will discuss several growth factors as mediators of intestinal regeneration and repair as well as potential therapeutic agents for NEC.

Granulocyte colony-stimulating-factor-producing hepatocellular carcinoma with extensive sarcomatous changes: report of a case

This report describes a rare case of hepatocellular carcinoma (HCC) producing granulocyte colony-stimulating factor (G-CSF). A 46-year-old male with chronic hepatitis B, who presented with fever, general malaise, loss of appetite, and weight loss, had a huge liver mass in the portal region. He had marked granulocytosis and his serum level of G-CSF was elevated. Complete tumor resection was performed, and the pathological assessment of the resected specimen revealed HCC with extensive sarcomatous changes and immunohistochemical staining for G-CSF and G-CSF receptor. Only a few cases of G-CSF-producing HCC have been reported, and this is the first case of G-CSF-producing HCC that also expressed G-CSF receptor.

The role of granulocyte colony-stimulating factor in the neutrophilia observed in the fetal inflammatory response syndrome

OBJECTIVES

Fetal neutrophilia is present in two-thirds of cases with the fetal inflammatory response syndrome (FIRS). The mechanisms responsible for this finding have not been elucidated. Granulocyte colony-stimulating factor (G-CSF) is the primary physiologic regulator of neutrophil production and plays a key role in the rapid generation and release of neutrophils in stressful conditions (i.e., infection). The objective of this study was to determine: 1) whether FIRS was associated with changes in fetal plasma G-CSF concentrations; and 2) if fetal plasma G-CSF concentrations correlated with fetal neutrophil counts, chorioamnionitis, neonatal morbidity/mortality and cordocentesis-to-delivery interval.

STUDY DESIGN

Percutaneous umbilical cord blood sampling was performed in a population of patients with preterm labor (n=107). A fetal plasma interleukin-6 (IL-6) concentration >11 pg/mL was used to define FIRS. Cord blood G-CSF was measured by a sensitive and specific immunoassay. An absolute neutrophil count was determined and corrected for gestational age. Receiver operating characteristic (ROC) curve, survival analysis and Cox proportional hazard model were employed.

RESULTS

1) G-CSF was detected in all fetal blood samples; 2) fetuses with FIRS had a higher median fetal plasma G-CSF concentration than those without FIRS (P<0.001); 3) a fetal plasma G-CSF concentration ≥134 pg/mL (derived from an ROC curve) was associated with a shorter cordocentesis-to-delivery interval, a higher frequency of chorioamnionitis (clinical and histological), intra-amniotic infection, and composite neonatal morbidity/mortality than a fetal plasma concentration below this cut-off; and 4) a fetal plasma G-CSF concentration ≥134 pg/mL was associated with a shorter cordocentesis-to-delivery interval (hazard ratio 3.2; 95% confidence interval 1.8-5.8) after adjusting for confounders.

CONCLUSIONS

1) G-CSF concentrations are higher in the peripheral blood of fetuses with FIRS than in fetuses without FIRS; and 2) a subset of fetuses with FIRS with elevated fetal plasma G-CSF concentrations are associated with neutrophilia, a shorter procedure-to-delivery interval, chorio-amnionitis and increased perinatal morbidity and mortality.

Effect of pasteurization on selected immune components of donated human breast milk

OBJECTIVE

Pasteurized, donated milk is increasingly provided to preterm infants in the absence of mother's own milk. The aim of this study was to determine the effect of pasteurization on the concentration of selected components in donated human breast milk.

STUDY DESIGN

Donated milk from 34 mothers was pooled into 17 distinct batches (4 mothers per batch). Aliquots of each batch were then Holder pasteurized (62.5 °C for 30 min). Interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-2, IL-4, IL-5, IL-8, IL-10, IL-12p70 and IL-13 were measured in a multiplex enzyme-linked immunosorbent assay (ELISA). Granulocyte colony-stimulating factor (G-CSF), heparin-binding epidermal-like growth factor (HB-EGF) and hepatocyte growth factor (HGF) were measured by ELISA. Lipids were assessed by gas chromatography and gangliosides by the resorcinol-HCl reaction.

RESULT

IFN-γ, TNF-α, IL-1β, IL-10 and HGF were significantly reduced by pasteurization (P<0.05). Gangliosides were not affected, but the proportion of medium-chain saturated fats was increased (P<0.05) with a trend towards a decreased proportion of oleic acid (P=0.057).

CONCLUSION

Pasteurization significantly reduced the concentration of several immunoactive compounds present in breast milk, but did not have an impact on others.

In the critically ill, nothing-by-mouth infant, would enteral administration of simulated amniotic fluid improve feeding tolerance compared with the current practice of no therapy? An evidence-based review

Necrotizing enterocolitis (NEC ) can be a devastating disease in the NIC U population. The current standard of practice of not providing enteral nutrition to the critically ill and the premature infant is thought to result in pathophysiologic changes of the gastrointestinal (GI) tract that may result in the development of NEC. Various methods of preventing or reducing the incidence of NEC in the NIC U have been explored. One such method is the enteral administration of simulated amniotic fluid (SAF). This article compares, contrasts, and reviews the available evidence regarding the use of SAF feedings as a means of reducing GI tract changes associated with nothing-by-mouth (NPO) status.

Effect of pasteurization on immune components of milk: implications for feeding preterm infants

It has been unequivocally proven that human breast milk is the ideal source of nutrition for infants. However, mothers of preterm infants face a number of barriers to providing sufficient milk volume to their babies, who are at risk for developing necrotizing enterocolitis (NEC). Donated milk, distributed through milk banks, is becoming a desirable alternative to formula feeding, and is increasingly being considered for hospitalized, preterm infants in North America. Donor milk in North America is pasteurized (62.5 °C, 30 min) to remove possible infectious contaminants; a number of immune and bioactive components are either partially or entirely inactivated by this process. Identifying the impact of pasteurization on immune components of breast milk has been the focus of numerous research studies over the past several decades. The objective of this review is to summarize the literature on the feeding of pasteurized donor milk to preterm infants and the current understanding of the impact of pasteurization on immune components of breast milk, with particular reference to those implicated in the prevention of NEC.

Oropharyngeal administration of colostrum to extremely low birth weight infants: theoretical perspectives

Studies in adults have shown that the oropharyngeal route can be used to effectively and safely administer interferon-alpha, an immune cell-derived cytokine, to patients who are unable to tolerate its parenteral administration. The mechanism for this appears to be the stimulatory effects of the cytokine, on the oropharyngeal-associated lymphoid tissue system. Own mother's colostrum (OMC) is rich in cytokines and other immune agents that provide bacteriostatic, bacteriocidal, antiviral, anti-inflammatory and immunomodulatory protection against infection. OMC may be especially protective for the extremely low birth weight (ELBW) infant in the first days of life; however clinical instability typically precludes enteral feedings during this period. Oropharyngeal administration is a potential alternative method of providing OMC. Oropharyngeal administration of OMC may have immunomodulatory effects on the recipient infant, and would be especially beneficial to the ELBW infant who would otherwise remain nil per os during the first days of life.

Antiinfective properties of human milk

The unfavorable effects of neonatal immunodeficiency are limited by some naturally occurring compensatory mechanisms, such as the introduction of protective and immunological components of human milk in the infant. Breast-feeding maintains the maternal-fetal immunological link after birth, may favor the transmission of immunocompetence from the mother to her infant, and is considered an important contributory factor to the neonatal immune defense system during a delicate and crucial period for immune development. Several studies have reported that breast-feeding, because of the antimicrobial activity against several viruses, bacteria, and protozoa, may reduce the incidence of infection in infants. The protection from infections may be ensured either passively by factors with antiinfective, hormonal, enzymatic, trophic, and bioactive activity present in breast milk, or through a modulator effect on the neonatal immune system exerted by cells, cytokines, and other immune agents in human milk.

Host factors in amniotic fluid and breast milk that contribute to gut maturation

The gut represents a complex organ system with regional differences, which reflect selective digestive and absorptive functions that change constantly in response to bodily requirements and the outside milieu. As a barrier to the external environment, gut epithelium must be renewed rapidly and repeatedly. Growth and renewal of gut epithelial cells is dependent on controlled cell stimulation and proliferation by a number of signaling processes and agents, including gut peptides-both endogenous and exogenous sources. This cascade of events begins during fetal development; with the ingestion of amniotic fluid, this process is enhanced and continued during infancy and early childhood through the ingestion of human milk. Events influenced by amniotic fluid during fetal development and those influenced by human milk that unfold after birth and early childhood to render the gut mature are presented.

Role of epidermal growth factor and other growth factors in the prevention of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) presents as the most common gastrointestinal emergency during the neonatal period and results in ulceration and necrosis of the distal small intestine and proximal colon. The etiology of NEC remains unknown. Based on the complexity of gut development, multiple growth factors and cytokines may be needed to synergistically support the developing gut. Epidermal growth factor (EGF) has been shown to play an important role in intestinal cell restitution, proliferation, and maturation. EGF is found in abundant quantities in many fluids, including the gastrointestinal tract, amniotic fluid, breast milk, and saliva. Preliminary clinical trials using EGF in neonates diagnosed with NEC have been shown to promote repair of intestinal epithelium. Additionally, other growth factors are also emerging as potential treatment modalities, including erythropoietin, granulocyte colony stimulating factor, and heparin-binding EGF. The role of EGF and other growth factors in the pathogenesis and prevention of NEC will be reviewed.

Treating feeding intolerance with an enteral solution patterned after human amniotic fluid: a randomized, controlled, masked trial

OBJECTIVE

Feeding intolerance is a common problem in the neonatal intensive care unit (NICU) and some cases might be causally related to atrophic changes in the small bowel mucosa. We speculated that for such patients, feeding tolerance might improve after oral administration of enterocyte growth factors in a sterile, isotonic solution patterned after amniotic fluid.

STUDY DESIGN

Twenty neonates meeting criteria for feeding intolerance were eligible for this trial. They were randomized to either Group 1 (test solution) or Group 2 (control). Group 1 received 2.5 ml of test solution/kg every 3 h by oral-gastric or nasal-gastric (OG/NG) tube. This was begun when the patient was NPO because of feeding intolerance and continued until 80 ml/k/day of milk feedings were tolerated, or for a maximum of 7 days. Group 2 received a sham OG/NG administration every 3 h, until 80 ml/k/day of milk feedings were tolerated, or for a maximum of 7 days. Only the bedside nurse and the NICU pharmacist were aware which patients received the test solution and which received the sham administrations. The volumes of milk feedings were increased by order of the attending neonatologist and nurse practitioner. The study outcome was enteral calories/kg/day during and for 7 days after the cessation of the treatments.

RESULTS

Eleven patients were randomized to receive the test solution and nine to receive sham administrations. At study entry, the two groups were not different in gestational age, postnatal age, signs of feeding intolerance or cal/k/day taken enterally during the previous 3 days. The study doses were given for an average of just under 6 days (range, 2 to 7 days). During the week following the administrations, the test solution recipients trended toward more enteral calories. Specifically, they had an increase averaging 78+/-20.8 cal/k/day more than before the study, whereas the sham recipients had an increase averaging 55.9+/-33 cal/k/day more than before the study (P=0.05 for a one-sided test and P=0.10 for a two-sided test). The test solution recipients also had a trend toward fewer formula changes than did the sham recipients (P=0.10). In this small, randomized, controlled, masked trial, the administration of a sterile, non-caloric, growth factor containing solution patterned after human amniotic fluid was associated with trends that we interpret as reflecting better tolerance of milk feedings. On this basis, we suggest that a phase III efficacy trial should be accomplished, using the present data for sample size calculations.

Protective effects of recombinant human granulocyte colony stimulating factor in a rat model of necrotizing enterocolitis

The role of cytokines and growth factors in the pathophysiology of neonatal necrotizing enterocolitis (NEC) is not defined clearly yet. The aim of this study was to determine the effects of recombinant human granulocyte colony stimulating factor (G-CSF) on intestinal cells in hypoxia-induced experimental NEC in rats. The study was experimented on Sprague Dawley rat pups. Group 1 (untreated, n = 7) rats were subjected to hypoxia-reoxygenation (H/O) and then were returned to standard conditions. Group 2 (G-CSF treated, n = 7) rats were subjected to H/O, and then were treated with G-CSF (100 microg/kg enterally) for 5 days. Group 3 was served as nonhypoxic controls. All animals were killed on day five, and histological examination was performed on intestinal samples. There were no histopathological changes in the control group. The histological findings in untreated rats were similar to those seen in neonatal NEC, with destruction of villi and crypts with extension to the muscularis layer. Intestinal damage was mild in group 2 and these histological changes were better than group 1, and worse than group 3. The mean of histologic grade of group 1 was 2.4 (range 2-3), and in the group 2, it was 1.2 (range 0-2). A difference was found when two groups were compared with each other (P < 0.05). In an experimental model of NEC, G-CSF could have a protective effect on intestinal damage.

Lipid malabsorption persists after weaning in rats whose dams were given GLP-2 and dexamethasone

Glucagon-like peptide-2 (GLP-2) enhances intestinal growth and absorption in mature animals, and glucocorticosteroids (GC) increase the sugar and lipid uptake in adult animals. However, the role of GC and GLP-2 in the ontogeny of lipid absorption is unknown. We hypothesized that GLP-2 and the GC dexamethasone (DEX), when administrated to rat dams during pregnancy and lactation, would enhance lipid uptake in the offspring. Rat dams were treated in the last 10 d of pregnancy and during lactation with GLP-2 [0.1 microg/g/d subcutaneous (sc)], DEX (0.128 microg/g/d sc), GLP-2 + DEX, or a placebo. Sucklings were sacrificed at 19-21 d of age, and weanlings were sacrificed 4 wk later. Lipid uptake was assessed using an in vitro ring uptake method. Although DEX and GLP-2 + DEX increased the jejunal mass, the jejunal lipid uptake was unchanged. In contrast, GLP-2, DEX, and GLP-2 + DEX reduced the ileal lipid uptake in suckling and weanling rats. This reduction was not due to alterations in intestinal morphology or to changes in fatty acid-binding protein abundance, but it was partially explained by an increase in the effective resistance of the intestinal unstirred water layer. In sucklings, DEX dramatically reduced the jejunal lipid uptake to levels similar to those seen in weanlings, such that the normal ontogenic decline in lipid uptake was not observed. Giving dams GLP-2 or DEX during pregnancy and lactation reduced lipid uptake in the offspring, and this persisted for at least 1 mon. The impact this may have on the nutritional well-being of the animal in later life is unknown.

Enteral granulocyte colony-stimulating factor for the treatment of mild (stage I) necrotizing enterocolitis: a placebo-controlled pilot study

BACKGROUND/PURPOSE

The presence of granulocyte colony-stimulating factor (G-CSF) in human milk and the expression of G-CSF receptors on intestinal villous enterocytes of neonates suggest that G-CSF has a role in the development and integrity of the gastrointestinal tract. We hypothesized that enteral recombinant human G-CSF (rhG-CSF) given to preterm infants with necrotizing enterocolitis (NEC) in the earlier stages could protect against disease progression and complications.

METHODS

Preterm infants with mild (stage I) NEC (n = 18) were assigned to receive enteral rhG-CSF (n = 8) or placebo (n = 10) for 5 days from the first day of the diagnosis. Clinical and gastrointestinal parameters were followed during the whole period of hospitalization.

RESULTS

In the study group, none of the infants with stage I NEC had a clinical progression to stage II or III, whereas in the control group, 5 (50%) infants with stage I NEC had a disease progression to stage II or III (P < .05). In the study group, the time required for the resolution of clinical and radiological findings of NEC and the total duration of systemic therapy and hospitalization were significantly shorter than the control group (P < .001).

CONCLUSION

Enteral rhG-CSF treatment could prevent the progression of mild (stage I) NEC to further stages and decrease the time required for the resolution of clinical and radiological signs of the disease.

Interleukin-2 in human milk: a potential modulator of lymphocyte development in the breastfed infant

Development of lymphocyte subpopulations and response to antigen exposure will be influenced by the limited ability of neonates to produce cytokines. In the case of cytokines such as interleukin (IL)-2 which are potent T lymphocyte regulators but poorly produced by newborn infants, the supply of cytokines through human milk could alleviate an immunological deficit and potentially aid the maturation of the immune system. We analysed human milk from 52 mothers (15-357 days postpartum) by ELISA to determine levels of aqueous IL-2, as well as production by human milk cells. IL-2 was detectable (>8 pg/mL) in the aqueous phase of 81% of all day 1 samples with no significant difference found in the mean concentration over 3 consecutive days. IL-2 was produced constitutively at detectable levels by 57% of milk cell samples and production was significantly increased by stimulation with Con A (380%). No correlation was found between aqueous and cellular IL-2, however there was a significant correlation between milk aqueous IL-2 and serum IL-2. This is the first report of IL-2 in the aqueous phase of human milk. A supply of exogenous IL-2 in human milk may provide the suckling infant with important immunological signals during a significant stage of T cell development.

A phase 1 trial testing an enteral solution patterned after human amniotic fluid to treat feeding intolerance

OBJECTIVE

Feeding intolerance is a common problem in neonates; in some cases it may be related to atrophic changes in the small bowel mucosa. In these infants, feeding tolerance might improve after oral administration of enterocyte growth factors in a sterile, isotonic, noncaloric solution patterned after human amniotic fluid.

STUDY DESIGN

Ten infants who met the study criteria for feeding intolerance were enrolled in this pilot trial. The test solution was administered, 2.5 mL/kg every 3 hours, until 80 mL/kg/day of milk feedings were tolerated, or for a maximum of 7 days. When milk feedings were prescribed, they were mixed with the test solution. Volumes of milk feedings were increased in amounts determined by the attending neonatologist and neonatal nurse practitioner. The outcome was the net average enteral kilocalories per kilogram of body weight per day (kcal/kg/day) for 3 periods: (1) the 3 days before the test treatment was begun, (2) the days the test treatment was administered, and (3) the 7 days following cessation of the test treatment.

RESULTS

At study entry the infants' chronological ages ranged from 3 to 65 days. All infants tolerated the test solution, which was given for a mean of 5 days (range 3 to 7 days). During that period, the infants received more enteral calories (mean 18 kcal/kg/day, range 1 to 32) than during the preceding 3 day period (mean 3 kcal/kg/day, range 0 to 7, P < 0.05). During the 7 days following the test treatment the infants received 87 enteral kcal/kg/day (range 11 to 109, P < 0.02 compared to the treatment period).

CONCLUSIONS

In this Phase 1 pilot trial, 10 heterogeneous infants in the neonatal intensive care unit with feeding intolerance had a significant increase in milk feedings after treatment with a sterile, isotonic, noncaloric solution patterned after human amniotic fluid.

Enteral administration of a simulated amniotic fluid to very low birth weight neonates

OBJECTIVE

To reduce feeding intolerance among very low birth weight neonates.

STUDY DESIGN

A total of 10 neonates with birth weights of 750 to 1250 g were given oral-gastric boluses (2.5 ml/kg every 3 hours) of a solution patterned after amniotic fluid. When milk feedings were begun the milk was mixed with the test solution. The solution was given at a constant daily dose of 20 ml/kg/day while the volumes of milk feedings were gradually increased. When milk feedings reached 80 ml/kg/day the test solution was discontinued. A comparison group consisted of neonates who met study criteria but were cared for during the period immediately preceding the study. The outcome was the number of calories taken enterally over the first 21 days of life.

RESULTS

The test solution was begun an average of 27 hours after birth (range, 4 to 45). In the test group the first milk feedings were introduced 74 hours after birth (range, 18 to 144), which was similar to the time milk was introduced in the comparison subjects (79 hours; range, 18 to 168). After milk feedings were started, the test patients had a total of four NPO days (0.4 NPO days per patient) during their first 21 days, while the comparison group had 34 NPO days (3.4 NPO days per patient). During the first 14 days of life the test solution recipients had a median of 26.5 enteral cal/kg/day (range, 4.3 to 68.9), while the comparison neonates had 8.5 (range, 0.2 to 25; p < 0.05). During the first 21 days of life the test solution recipients had a median of 56.9 enteral cal/kg/day (range, 11.5 to 89.4), while the comparison neonates had 19.2 (range, 0.9 to 52.8; p < 0.05).

CONCLUSION

In all, 10 VLBW infants tolerated the test solution for periods up to 14 days with no significant adverse effects. A randomized trial to determine whether this solution reduces feeding intolerance among VLBW neonates should be conducted.

Managing passively acquired autoimmune neonatal neutropenia: a case study

Pregnant women with autoimmune neutropenia (AIN) and circulating neutrophil-specific autoantibodies can deliver neutropenic neonates at risk of sepsis. We report the case of a woman who had two such pregnancies. The woman had been on prophylactic granulocyte colony-stimulating factor (G-CSF) treatment, but this was ceased prior to conception in both pregnancies. In the first pregnancy, there was no monitoring or interventions, and the neonate was neutropenic and required intensive care treatment. In the second pregnancy, the maternal neutrophil autoantibody level was monitored, and G-CSF treatment was introduced in the third trimester. The second infant had no neutropenia at delivery and an excellent Apgar score. We discuss the management strategy in the second pregnancy that included monitoring of serial titres of the maternal autoantibody and the introduction of G-CSF in the third trimester, which may have contributed to a more favourable clinical outcome. This may assist other clinicians faced with similar dilemmas in the future.

Microarray analysis of human milk cells: persistent high expression of osteopontin during the lactation period

To continue the search for immunological roles of breast milk, cDNA microarray analysis on cytokines and growth factors was performed for human milk cells. Among the 240 cytokine-related genes, osteopontin (OPN) gene ranked top of the expression. Real-time PCR revealed that the OPN mRNA levels in colostrum cells were approximately 100 times higher than those in PHA-stimulated peripheral blood mononuclear cells (PBMNCs), and 10 000 times higher than those in PB CD14(+) cells. The median levels of OPN mRNA in early milk or mature milk cells were more than three times higher than those in colostrum cells. Western blot analysis of human milk showed appreciable expression of full-length and short form proteins of OPN. The concentrations of full-length OPN in early milk or mature milk whey continued to be higher than those in colostrum whey and plasma as assessed by ELISA. The early milk (3-7 days postpartum) contained the highest concentrations of OPN protein, while the late mature milk cells (1 years postpartum) had the highest expression of OPN mRNA of all the lactating periods. The results of immunohistochemical and immunocytochemical staining indicated that OPN-producing epithelial cells and macrophages are found in actively lactating mammary glands. These results suggest that the persistently and extraordinarily high expression of OPN in human milk cells plays a potential role in the immunological development of breast-fed infants.

Role of cytokines in human intestinal villous development

Villous development of the intestine is beginning to be understood in terms of the underlying molecular mechanisms. There is increasing information on the role of cytokines as extrinsic regulators in this process. This article summarizes information available on various cytokines that have been studied in this context.

Hematopoietic growth factors in neonatal medicine: the use of enterally administered hematopoietic growth factors in the neonatal intensive care unit

The practice of complete bowel rest in prematurely delivered neonates and those who have undergone surgery for congenital anomalies of the gastrointestinal (GI) tract is common in neonatal intensive care units (NICU). However, increased recognition of the critical role of growth factors in GI development suggests that this practice might be modified to include the administration of synthetic amniotic fluid-like solutions designed to bridge the neonate between their intra-uterine environment and that of the NICU. This article reviews advances in administering synthetic amniotic fluid-like solutions in the NICU.

Abnormal intestinal histology in neonates with congenital anomalies of the gastrointestinal tract

In animal models, when swallowing is experimentally prevented in utero, bowel length and weight are reduced, and villus height, crypt depth, and villus function are retarded. Little is known about the intestinal histology in infants with gastrointestinal (GI) tract anomalies. We examined the histological architecture of the intestine in neonates with GI anomalies in comparison to that of normal fetuses. Villus height, area, and length and crypt depth of normal fetuses were quantified in the proximal small bowel (n = 11) and measurements compared to those of surgical specimens of neonates with congenital anomalies of the GI tract (n = 16). Villus height and area and lamina propria height and area increased linearly from 8 to 24 weeks of gestation. In infants with anomalies of the GI tract, the villi were blunted and lacked normal histological architecture, the crypts were disorganized, and the crypt depth was significantly decreased (p = 0.004). Enterocyte height and area were significantly greater in neonates with congenital anomalies of the GI tract. The intestinal histology in neonates with congenital anomalies of the GI tract differs significantly from that of normal fetuses.

Recombinant granulocyte colony-stimulating factor administered enterally to neonates is not absorbed

Granulocyte colony-stimulating factor (G-CSF) is present in liquids swallowed by the fetus and neonate; specifically, amniotic fluid, colostrum, and human milk. The swallowed G-CSF has local effects on enteric cells, which express the G-CSF receptor. However, some portion of the G-CSF ingested by the fetus and neonate might be absorbed into the circulation and have systemic actions, such as stimulating neutrophil production. To assess this possibility we sought to determine if circulating G-CSF concentrations of neonates increase after enteral administration of recombinant human granulocyte colony-stimulating factor (rhG-CSF). This was a single-center, prospective, blinded, randomized, 2 x 2 crossover study, with each infant receiving 1 dose of rhG-CSF (100 microg/kg) and 1 dose of placebo. Plasma G-CSF concentrations were measured at 2 and 4 hours after administration of the test solution. No significant change in plasma G-CSF concentration was observed after the enteral administration of rhG-CSF. On this basis, we conclude that orally administered rhG-CSF is not absorbed in significant quantities, and we speculate that the G-CSF swallowed by the fetus and neonate has local but not systemic effects.

Enteral administration of hematopoietic growth factors in the neonatal intensive care unit

By 20 wk of gestation, the human fetal gastrointestinal (GI) tract morphologically resembles that of the term infant, but functional development is limited before 26 wk. By 30 wk of gestation, the fetus has the capacity for limited digestion and enteral absorption. GI growth and development continue postnatally. Trophic factors, including nutrients, peptides, hormones and growth factors, are recognized as having important influences on the morphology and histology of the developing GI tract. Other trophic factors are important in adaptation and repair following injury. Many such factors are provided in utero via amniotic fluid swallowing and later by human colostrum and milk.

CONCLUSION

This review discusses cytokines with known GI trophic effects, either in vitro or in vivo, and focuses on those cytokines that have been used in the neonatal intensive care unit.

Circulating granulocyte colony-stimulating factor, C-X-C, and C-C chemokines in children with Escherichia coli O157:H7 associated hemolytic uremic syndrome

Leukocytes are implicated in the pathogenesis of diarrhea-associated hemolytic uremic syndrome (D(+) HUS). We hypothesized that increased circulating levels of granulocyte colony-stimulating factor (G-CSF), and the chemokines epithelial cell-derived neutrophil-activating protein-78 (ENA-78), growth related oncogen-alpha (GRO-alpha), macrophage inflammatory protein-1beta (MIP-1beta), and monocyte chemotactic protein-1 (MCP-1) are related to the severity of illness in Escherichia coli O157:H7 infections. We compared the circulating concentrations of these mediators in the course of E. coli O157:H7 enteritis, hemorrhagic colitis, and HUS. Our data show that, on admission, children with HUS presented 10-fold abnormally increased levels of G-CSF (p < 0.007), 3-fold increased MIP-1beta concentrations (p < 0.001), and 2-fold lower values of ENA-78 (p < 0.0001). One week later, a further 4-fold decrease in ENA-78 concentration was noted (p < 0.0001) whereas MIP-1beta levels returned to normal. HUS patients requiring peritoneal dialysis showed 6-fold increased G-CSF (p < 0.001) and 5-fold decreased ENA-78 (p < 0.001) levels. On admission, children with uncomplicated O157:H7 hemorrhagic colitis (HC) presented 3-fold abnormally increased concentrations of G-CSF (p < 0.001) and MIP-1beta (p < 0.0001). Those with O157:H7 enteritis but no bloody stools showed higher rates of abnormal GRO-alpha, MIP-1beta, and MCP-1 measurements than children with O157:H7 HC or HUS: GRO-alpha (50% enteritis, 36% HC, 17% HUS; p < 0.06), MIP-1beta (40% enteritis, 22% HC, 11% HUS; p < 0.02), MCP-1 (77% enteritis, 20% HC, 18% HUS; p < 0.0001). The data indicates that GRO-alpha, MIP-1beta, and MCP-1 are produced during E. coli O157:H7 enteritis, whether or not HC or HUS develops. Our data suggest that children with O157:H7 associated HUS may present abnormally increased circulating levels of G-CSF and decreased ENA-78 concentrations. The mechanisms responsible for leukocytes recruitment in O157:H7 infections are unclear and await further studies.

Updates in pediatric nutrition

Ongoing research in several areas of pediatric nutrition has new practical applications for community-based pediatricians. For example, a fresh understanding of risk factors for rickets persuades pediatricians to recognize and treat this disease, which was thought to be nearly extinct in the modern industrialized world. Similarly, an expanded awareness of the antibacterial components of breast milk encourages a more complete dialogue between pediatricians and new mothers about the potential benefits of breast-feeding. For those infants with feeding intolerance, new data help to refine the indications for hypoallergenic formulas, which are increasingly recommended for children with a variety of symptoms. The past year also has seen breakthroughs in our understanding of supplemental nutrition for children. Vitamin A may provide direct benefits for the most vulnerable of children, namely premature infants at high risk for lung disease. At the other end of the pediatric spectrum, adolescent athletes seeking to enhance their performance are consuming poorly studied sports supplements that may not be beneficial and may even be toxic. Finally, a greater appreciation for the epidemic of obesity that is sweeping the United States and other countries suggests that children at high risk may represent a far more diverse population than had been recognized previously.

Stability of filgrastim and epoetin alfa in a system designed for enteral administration in neonates

OBJECTIVE

To determine the stability of recombinant granulocyte colony-stimulating factor (rG-CSF, filgrastim) and recombinant erythropoietin (rEpo, epoetin alfa) in a solution designed for enteral administration in the neonatal intensive care unit.

DESIGN

Filgrastim and epoetin alfa were added to a solution with NaCl 0.9%, sodium acetate, potassium chloride, and human albumin in concentrations designed to mimic human amniotic fluid. Additionally, the solution was dripped through polyvinyl chloride feeding tubes to simulate feedings, and aliquots were collected before, during, and after priming of the tube. Other aliquots were either frozen immediately, stored at room temperature, or refrigerated for 0, 6, 12, 18, and 24 hours.

MAIN OUTCOME MEASURES

Filgrastim and epoetin alfa concentrations in the various aliquots were compared with the concentrations in the original solution.

RESULTS

Filgrastim and epoetin alfa concentrations were stable for at least 24 hours when refrigerated and for at least three weeks when frozen. At room temperature, filgrastim was stable for 18 hours and epoetin alfa for 24 hours. Filgrastim concentrations did not vary significantly before, during, or after priming of the feeding tube, whereas epoetin alfa concentrations decreased significantly unless the feeding tube was primed with 10 mL of solution.

CONCLUSIONS

Filgrastim and epoetin alfa were stable in our amniotic fluid-like solution. In this respect, our solution is suitable for enteral administration to patients in the neonatal intensive care unit.

A practical approach to evaluating and treating neutropenia in the neonatal intensive care unit

Neutropenia is a relatively common problem in the NICU, recognized in as many as 8% of patients at some time during their hospital stay. In most instances, neutropenia among NICU patients is of short duration and has little influence on outcome. In other cases it is prolonged and severe, and constitutes a serious antimicrobial defense deficiency. When a neonatologist discovers a low blood neutrophil count, choices must be made regarding further evaluation and treatment. The authors hope that the information provided in this article is useful in making these choices.