The effect of lactoferrin supplementation on death or major morbidity in very low birthweight infants (LIFT): a multicentre, double-blind, randomised controlled trial

Lactoferrin Supplementation in Preventing and Protecting from SARS-CoV-2 Infection: Is There Any Role in General and Special Populations? An Updated Review of Literature

At the beginning of the pandemic, SARS-CoV-2 infection represented a great medical burden worldwide, as targeted and effective therapeutic options were lacking. This resulted in the revival of existing molecules and the increasing popularity of over-the-counter nutritional supplements. Among the latter, lactoferrin has been investigated as an adjuvant in COVID-19 therapy with conflicting results, mainly depending on different study designs. Considering that lactoferrin is one of the main components of human breast milk with anti-microbial and anti-inflammatory activity, it is conceivable that such bioactive molecule could be effective in supporting anti-SARS-CoV-2 infection therapy, especially in infants and pregnant women, two subpopulations that have been poorly evaluated in the existing clinical trials. This narrative review is intended to offer insight into the existing literature on lactoferrin's biological functions and protective effects against COVID-19, with a special focus on pregnant women and their infants.

Invasive Candida Infections in Neonatal Intensive Care Units: Risk Factors and New Insights in Prevention

Invasive Candida infections represent a significant cause of morbidity and mortality in neonatal intensive care units (NICUs), with a particular impact on preterm and low-birth-weight neonates. In addition to prematurity, several predisposing factors for Candida colonization and dissemination during NICU hospitalization have been identified, including prolonged exposure to broad-spectrum antibiotics, central venous catheters, parenteral nutrition, corticosteroids, H2 antagonist administration, and poor adherence to infection control measures. According to the literature, the implementation of antifungal prophylaxis, mainly fluconazole, in high-risk populations has proven to be an effective strategy in reducing the incidence of fungal infections. This review aims to provide an overview of risk factors for invasive Candida infections and current perspectives regarding antifungal prophylaxis use. Recognizing and reducing people's exposure to these modifiable risk factors, in conjunction with the administration of antifungal prophylaxis, has been demonstrated to be an effective method for preventing invasive candidiasis in susceptible neonatal populations.

The evolution of nutritional care in preterm infants with a focus on the extreme preterm infant

The evolution of nutritional care in preterm infants, particularly those classified as extremely preterm, has undergone significant advancements in recent years. These infants, born at less than 28 weeks of gestation, face unique challenges related to their elevated nutrient requirements, underdeveloped organ systems and minimal reserves, posing a need for timely and specialised nutritional strategies. Historically, the nutritional management of preterm infants focussed on short-term goals to promote survival. In recent years, the focus has shifted to the quality of nutrient provision to optimise neurodevelopment and longer-term health outcomes. This review highlights the shift from a generalised nutritional approach to a robust, evidence-based approach for preterm infants, acknowledging the intricate interplay between nutrition, holistic care and developmental outcomes. As neonatal care continues to evolve, ongoing research will refine nutritional interventions, optimise growth and enhance the long-term health outcomes of these vulnerable infants.

Assessment of food supplements for the prevention of necrotizing enterocolitis in preterm neonates: A systematic review and network meta-analysis

BACKGROUND

The network meta-analysis (NMA) investigated the efficacy of six food supplements, namely glutamine, arginine, lactoferrin, prebiotics, synbiotics, and probiotics, in preventing necrotizing enterocolitis in premature infants.

METHODS

MEDLINE, Embase, and Cochrane Library were searched. Randomized controlled trials comparing different food supplements for premature infants were included.

RESULTS

Probiotics (OR, 0.47; 95% CrI, 0.33-0.63), arginine (OR, 0.38; 95% CrI, 0.14-0.98), glutamine (OR, 0.30; 95% CrI, 0.079-0.90), and synbiotics (OR, 0.13; 95% CrI, 0.037-0.37). were associated with a decreased incidence of NEC. Only probiotics (OR, 0.81; 95% CrI, 0.69-0.95) and lactoferrin (OR, 0.74; 95% CrI, 0.54-0.92) achieved lower risk of sepsis. Probiotics (OR, 0.58; 95% CrI, 0.40-0.79), prebiotics (OR, 0.23; 95% CrI, 0.043-0.86), and synbiotics (OR, 0.15; 95% CrI, 0.035-0.50) were associated with lower odds of mortality. Probiotics (MD, -2.3; 95% CrI: -3.7- -0.63) appeared to have earlier age of attainment of full feeding.

CONCLUSIONS

Based on this NMA, probiotics and synbiotics had the potential to be the top two preferable food supplements.

Effect of Lactoferrin on Clinical Outcomes of Hospitalized Patients with COVID-19: The LAC Randomized Clinical Trial

As lactoferrin is a nutritional supplement with proven antiviral and immunomodulatory abilities, it may be used to improve the clinical course of COVID-19. The clinical efficacy and safety of bovine lactoferrin were evaluated in the LAC randomized double-blind placebo-controlled trial. A total of 218 hospitalized adult patients with moderate-to-severe COVID-19 were randomized to receive 800 mg/die oral bovine lactoferrin (n = 113) or placebo (n = 105), both given in combination with standard COVID-19 therapy. No differences in lactoferrin vs. placebo were observed in the primary outcomes: the proportion of death or intensive care unit admission (risk ratio of 1.06 (95% CI 0.63-1.79)) or proportion of discharge or National Early Warning Score 2 (NEWS2) ≤ 2 within 14 days from enrollment (RR of 0.85 (95% CI 0.70-1.04)). Lactoferrin showed an excellent safety and tolerability profile. Even though bovine lactoferrin is safe and tolerable, our results do not support its use in hospitalized patients with moderate-to-severe COVID-19.

Necrotizing enterocolitis in premature infants-A defect in the brakes? Evidence from clinical and animal studies

A key aspect of postnatal intestinal adaptation is the establishment of symbiotic relationships with co-evolved gut microbiota. Necrotizing enterocolitis (NEC) is the most severe disease arising from failure in postnatal gut adaptation in premature infants. Although pathological activation of intestinal Toll-like receptors (TLRs) is believed to underpin NEC pathogenesis, the mechanisms are incompletely understood. We postulate that unregulated aberrant TLR activation in NEC arises from a failure in intestinal-specific mechanisms that tamponade TLR signaling (the brakes). In this review, we discussed the human and animal studies that elucidate the developmental mechanisms inhibiting TLR signaling in the postnatal intestine (establishing the brakes). We then evaluate evidence from preclinical models and human studies that point to a defect in the inhibition of TLR signaling underlying NEC. Finally, we provided a framework for the assessment of NEC risk by screening for signatures of TLR signaling and for NEC prevention by TLR-targeted therapy in premature infants.

Endotoxin content in neonatal formulas, fortification, and lactoferrin products: association with outcomes and guidance on acceptable limits

While endotoxin (lipopolysaccharide) can be harmful and contribute to morbidity and mortality with Gram-negative sepsis or necrotizing enterocolitis in preterm infants, non-toxic amounts are produced as part of the neonatal microbiome and may be present in enteral nutrition and medications administered. The United States Food and Drug Administration has given guidance for endotoxin concentration limits for intravenous medications and fluids of 5 endotoxin units/kg/hour (120 endotoxin units/kg/day), but no guidance for amounts of endotoxin in enteral products. To determine baseline exposure to infants in the neonatal intensive care unit, we examined endotoxin content of enteral formulas and fortification used for preterm infants, as well as bovine lactoferrin products. We also examined endotoxin exposure and outcomes in very low birth weight infants. Endotoxin content was measured using kinetic chromogenic limulus amebocyte lysate analysis. Daily endotoxin exposure from enteral formulas ranged between < 75 to 7110 endotoxin units/kg and from lactoferrin products from 7 to 3720 endotoxin units/kg. In examining neonatal outcomes from a bovine lactoferrin product studied at three different escalating doses (100, 200, and 300 mg/kg/day), we measured endotoxin in the lactoferrin product and daily exposure was 1089 (N = 10), 2178 (N = 10) and 3287 (N = 11) endotoxin units/kg, respectively. There were no cases of necrotizing enterocolitis or mortality and no lactoferrin-related adverse effects in these patients. Enteral endotoxin daily exposures from lactoferrin products are similar to amounts in preterm enteral nutrition and appear safe and not associated with patient harm. Testing enteral products and establishing safety limits may improve care of high risk patients.

Mechanisms affecting the gut of preterm infants in enteral feeding trials: a nested cohort within a randomised controlled trial of lactoferrin

OBJECTIVE

To determine the impact of supplemental bovine lactoferrin on the gut microbiome and metabolome of preterm infants.

DESIGN

Cohort study nested within a randomised controlled trial (RCT). Infants across different trial arms were matched on several clinical variables. Bacteria and metabolite compositions of longitudinal stool and urine samples were analysed to investigate the impact of lactoferrin supplementation.

SETTING

Thirteen UK hospitals participating in a RCT of lactoferrin.

PATIENTS

479 infants born <32 weeks' gestation between June 2016 and September 2017.

RESULTS

10 990 stool and 22 341 urine samples were collected. Analyses of gut microbiome (1304 stools, 201 infants), metabolites (171 stools, 83 infants; 225 urines, 90 infants) and volatile organic compounds (314 stools, 117 infants) were performed. Gut microbiome Shannon diversity at 34 weeks corrected age was not significantly different between infants in the lactoferrin (mean=1.24) or placebo (mean=1.06) groups (p=0.11). Lactoferrin receipt explained less than 1% variance in microbiome compositions between groups. Metabolomic analysis identified six discriminative features between trial groups. Hospital site (16%) and postnatal age (6%) explained the greatest variation in microbiome composition.

CONCLUSIONS

This multiomic study identified minimal impacts of lactoferrin but much larger impacts of hospital site and postnatal age. This may be due to the specific lactoferrin product used, but more likely supports the findings of the RCT in which this study was nested, which showed no impact of lactoferrin on reducing rates of sepsis. Multisite mechanistic studies nested within RCTs are feasible and help inform trial interpretation and future trial design.

Effects of dietary supplementation of bovine lactoferrin on growth performance, immune function and intestinal health in weaning piglets

Weaning is a crucial period in the pig's life cycle, which is frequently followed by gastrointestinal (GI) infections, diarrhea and even death. This study focused on the impact of bovine lactoferrin (bLF) supplementation on the intestinal health of weaning piglets. Weaning piglets (Duroc × Landrace × Yorkshire, 23 days) were randomly allocated into four groups, which included negative control group (CON): basic diet; positive control group (ANT): basic diet + 20 mg/kg flavomycin + 100 mg/kg aureomycin; treatment group bLF-A: basic diet + 1 g/kg bLF; treatment group bLF-B: basic diet + 3 g/kg bLF. The result showed that dietary supplementation of bLF can improve growth performance and reduce diarrhea, which exhibits dose-dependency (P < 0.05). Compared with CON group, supplementation with bLF significantly improved immunity, and increased villus height and ratio of villus height/crypt depth at the small intestinal mucosa (P < 0.05). The mRNA expression of claudin-1, occludin and ZO-1 was greatly increased in the ileum of bLF group on days 7 and 14 (P < 0.05). Furthermore, the supplementation of bLF increased the abundance of Lactobacillus and Bifidobacterium and decreased the abundance of Escherichia coli in the cecum on day 7 (P < 0.05). The dietary supplementation of bLF enhanced the growth performance, reduced diarrhea rate in weaning piglets by improving intestinal immunity, morphology and barrier function, balancing intestinal microbiota. And bLF can be a promising feed additive in relieving stress situation of weaning piglets.

Babies, Bugs, and Barriers: Dietary Modulation of Intestinal Barrier Function in Early Life

The intestinal barrier is essential in early life to prevent infection, inflammation, and food allergies. It consists of microbiota, a mucus layer, an epithelial layer, and the immune system. Microbial metabolites, the mucus, antimicrobial peptides, and secretory immunoglobulin A (sIgA) protect the intestinal mucosa against infection. The complex interplay between these functionalities of the intestinal barrier is crucial in early life by supporting homeostasis, development of the intestinal immune system, and long-term gut health. Exclusive breastfeeding is highly recommended during the first 6 months. When breastfeeding is not possible, milk-based infant formulas are the only safe alternative. Breast milk contains many bioactive components that help to establish the intestinal microbiota and influence the development of the intestinal epithelium and the immune system. Importantly, breastfeeding lowers the risk for intestinal and respiratory tract infections. Here we review all aspects of intestinal barrier function and the nutritional components that impact its functionality in early life, such as micronutrients, bioactive milk proteins, milk lipids, and human milk oligosaccharides. These components are present in breast milk and can be added to milk-based infant formulas to support gut health and immunity. Expected final online publication date for the Annual Review of Nutrition, Volume 42 is August 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Immunological Effects of Adding Bovine Lactoferrin and Reducing Iron in Infant Formula: A Randomized Controlled Trial

OBJECTIVES

Compared to formula-fed infants, breastfed infants have a lower risk of infections. Two possible reasons for this are the presence of the anti-infective and anti-inflammatory protein lactoferrin and the lower level of iron in breast milk. We explored how adding bovine lactoferrin and reducing the iron concentration in infant formula affect immunology and risk of infections in healthy infants.

METHODS

In a double-blind controlled trial, term formula-fed (FF) Swedish infants (n = 180) were randomized to receive, from 6 weeks to 6 months of age, a low-iron formula (2 mg/L) with added bovine lactoferrin (1.0 g/L) (Lf+; n = 72); low-iron formula with no added lactoferrin (Lf-; n = 72); and standard formula at 8 mg/L iron and no added lactoferrin (control formula [CF]; n = 36). Cytokines, infections, and infection related treatments were assessed until 12 months of age.

RESULTS

No adverse effects were observed. There were no apparent effects on transforming growth factor beta (TGF-β)1, TGF-β2, tumor necrosis factor alfa (TNF-α) or interleukin2 (IL-2) at 4, 6, or 12 months, except of higher TGF-β2 at 6 months in the CF group in comparison to the low iron groups combined (P = 0.033). No significant differences in otitis, respiratory infections, gastroenteritis, or other monitored infections and treatments were detected for any of the study feeding groups during the first 6 months and only a few and diverging effects were observed between 6 and 12 months.

CONCLUSIONS

Adding bovine lactoferrin and reducing iron from 8 to 2 mg/L in infant formula was safe. No clinically relevant effects on cytokines or infection related morbidity were observed in this well-nourished and healthy population.

Clinical implications of preterm infant gut microbiome development

Perturbations to the infant gut microbiome during the first weeks to months of life affect growth, development and health. In particular, assembly of an altered intestinal microbiota during infant development results in an increased risk of immune and metabolic diseases that can persist into childhood and potentially into adulthood. Most research into gut microbiome development has focused on full-term babies, but health-related outcomes are also important for preterm babies. The systemic physiological immaturity of very preterm gestation babies (born earlier than 32 weeks gestation) results in numerous other microbiome-organ interactions, the mechanisms of which have yet to be fully elucidated or in some cases even considered. In this Perspective, we compare assembly of the intestinal microbiome in preterm and term infants. We focus in particular on the clinical implications of preterm infant gut microbiome composition and discuss the prospects for microbiome diagnostics and interventions to improve the health of preterm babies.

Intestinal Dysbiosis in the Infant and the Future of Lacto-Engineering to Shape the Developing Intestinal Microbiome

PURPOSE

The goal of this study was to review the role of human milk in shaping the infant intestinal microbiota and the potential of human milk bioactive molecules to reverse trends of increasing intestinal dysbiosis and dysbiosis-associated diseases.

METHODS

This narrative review was based on recent and historic literature.

FINDINGS

Human milk immunoglobulins, oligosaccharides, lactoferrin, lysozyme, milk fat globule membranes, and bile salt-stimulating lipase are complex multifunctional bioactive molecules that, among other important functions, shape the composition of the infant intestinal microbiota.

IMPLICATIONS

The co-evolution of human milk components and human milk-consuming commensal anaerobes many thousands of years ago resulted in a stable low-diversity infant microbiota. Over the past century, the introduction of antibiotics and modern hygiene practices plus changes in the care of newborns have led to significant alterations in the intestinal microbiota, with associated increases in risk of dysbiosis-associated disease. A better understanding of mechanisms by which human milk shapes the intestinal microbiota of the infant during a vulnerable period of development of the immune system is needed to alter the current trajectory and decrease intestinal dysbiosis and associated diseases.

Lactoferrin for Prevention and Treatment of Anemia and Inflammation in Pregnant Women: A Comprehensive Review

Pregnancy is a physiological state that demands higher level of nutrients, including vitamins and minerals, for the growth and maintenance of the fetus. Iron deficiency is a part of most common diet deficiencies in pregnancy and has high clinical significance leading to the development of syderopenic anemia and its consequences for mother and child, such as higher risk of perinatal death, susceptibility to infection, intra-uteral growth inhibition, prematurity and low birth weight. Hence, iron supplementation is recommended for pregnant women; however dietary intake of iron from most commercially available formulas is often insufficient due to iron-poor bioavailability, or have undesired side-effects in the gastrointestinal tract, resulting in a discouraging and distrustful attitude to such treatment. The results of numerous studies indicate that diet supplementation with lactoferrin (LTF), an iron-binding protein, may be advantageous in prophylaxis and treatment of iron deficiency anemia. LTF, administered orally, normalizes iron homeostasis, not only by facilitating iron absorption, but also by inhibiting inflammatory processes responsible for anemia of chronic diseases, characterized by a functional iron deficit for physiological processes. LTF also protects against infections and inflammatory complications, caused by diagnostic surgical interventions in pregnant women. Beneficial, multidirectional actions of LTF during pregnancy encompass, in addition, inhibition of oxidative stress, normalization of intestine and genital tract microbiota and carbohydrate-lipid metabolism, protection of intestine barrier function, promotion of wound healing, as well as hypotensive, analgesic and antistress actions. Bovine lactoferrin (BLTF) is readily available on the nutritional market and generally recognized as safe (GRAS) for use in human diet.

Is Lactoferrin Supplementation Beneficial for All Preterm Infants?

OBJECTIVE

 Human milk (HM) has antibacterial properties due to the presence of immune-modulators, including lactoferrin (LF). This study will determine effect(s) of HM maturation, fortification, and storage conditions on LF levels and its antibacterial properties.

STUDY DESIGN

 HM samples (n = 30) were obtained from preterm and term mothers. The LF levels were analyzed by ELISA, and the antibacterial activity was measured after inoculation with Escherichia coli.

RESULTS

 The highest level of LF in preterm HM was observed in the first week of lactation. However, storage of preterm HM at 4°C decreased LF levels significantly. Both LF levels and antibacterial activity in preterm HM was lower compared with term HM, but significantly higher than donor HM even after HM-based fortification. LF supplementation of donor HM improved its antibacterial activity.

CONCLUSION

 Preterm infants fed donor HM, formula, or stored HM at 4°C may benefits from LF supplementation to improve HM antibacterial properties.

KEY POINTS

· Milk LF levels vary with storage and maturity.. · Donor milk is deficient in LF even after adding HM-based fortification.. · Donor HM and formula fed infants may benefit from LF..

Enteral Feeding Interventions in the Prevention of Necrotizing Enterocolitis: A Systematic Review of Experimental and Clinical Studies

Necrotizing enterocolitis (NEC), which is characterized by severe intestinal inflammation and in advanced stages necrosis, is a gastrointestinal emergency in the neonate with high mortality and morbidity. Despite advancing medical care, effective prevention strategies remain sparse. Factors contributing to the complex pathogenesis of NEC include immaturity of the intestinal immune defense, barrier function, motility and local circulatory regulation and abnormal microbial colonization. Interestingly, enteral feeding is regarded as an important modifiable factor influencing NEC pathogenesis. Moreover, breast milk, which forms the currently most effective prevention strategy, contains many bioactive components that are known to support neonatal immune development and promote healthy gut colonization. This systematic review describes the effect of different enteral feeding interventions on the prevention of NEC incidence and severity and the effect on pathophysiological mechanisms of NEC, in both experimental NEC models and clinical NEC. Besides, pathophysiological mechanisms involved in human NEC development are briefly described to give context for the findings of altered pathophysiological mechanisms of NEC by enteral feeding interventions.

Antibacterial and Anti-biofilm Activity of the Human Breast Milk Glycoprotein Lactoferrin against Group B Streptococcus

Group B Streptococcus (GBS) is an encapsulated Gram-positive human pathogen that causes invasive infections in pregnant hosts and neonates, as well as immunocompromised individuals. Colonization of the human host requires the ability to adhere to mucosal surfaces and circumnavigate the nutritional challenges and antimicrobial defenses associated with the innate immune response. Biofilm formation is a critical process to facilitate GBS survival and establishment of a replicative niche in the vertebrate host. Previous work has shown that the host responds to GBS infection by producing the innate antimicrobial glycoprotein lactoferrin, which has been implicated in repressing bacterial growth and biofilm formation. Additionally, lactoferrin is highly abundant in human breast milk and could serve a protective role against invasive microbial pathogens. This study demonstrates that human breast milk lactoferrin has antimicrobial and anti-biofilm activity against GBS and inhibits its adherence to human gestational membranes. Together, these results indicate that human milk lactoferrin could be used as a prebiotic chemotherapeutic strategy to limit the impact of bacterial adherence and biofilm formation on GBS-associated disease outcomes.

Breast Milk: A Source of Functional Compounds with Potential Application in Nutrition and Therapy

Breast milk is an unbeatable food that covers all the nutritional requirements of an infant in its different stages of growth up to six months after birth. In addition, breastfeeding benefits both maternal and child health. Increasing knowledge has been acquired regarding the composition of breast milk. Epidemiological studies and epigenetics allow us to understand the possible lifelong effects of breastfeeding. In this review we have compiled some of the components with clear functional activity that are present in human milk and the processes through which they promote infant development and maturation as well as modulate immunity. Milk fat globule membrane, proteins, oligosaccharides, growth factors, milk exosomes, or microorganisms are functional components to use in infant formulas, any other food products, nutritional supplements, nutraceuticals, or even for the development of new clinical therapies. The clinical evaluation of these compounds and their commercial exploitation are limited by the difficulty of isolating and producing them on an adequate scale. In this work we focus on the compounds produced using milk components from other species such as bovine, transgenic cattle capable of expressing components of human breast milk or microbial culture engineering.

Lactoferrin: an overview of its main functions, immunomodulatory and antimicrobial role, and clinical significance

Lactoferrin (LF), a glycoprotein found in mucosal secretions, is characterized by a wide range of functions, including immunomodulatory and anti-inflammatory activities. Moreover, several investigations confirmed that LF displays high effectiveness against multiple bacteria and viruses and may be regarded as a potential inhibitor of enveloped viruses, such as presently prevailing SARS-CoV-2. In our review, we discuss available studies about LF functions and bioavailability of different LF forms in in vitro and in vivo models. Moreover, we characterize the potential benefits and side effects of LF use; we also briefly summarize the latest clinical trials examining LF application. Finally, we point potential role of LF in inflammatory bowel disease and indicate its use as a marker for disease severity.

Dose escalation study of bovine lactoferrin in preterm infants: getting the dose right

Lactoferrin as a nutritional enteral supplement has emerged as a novel preventative therapy against serious infections in preterm infants, although neonatal studies have demonstrated variable results, in part due to the lack of pharmacokinetic data and differences in the products tested. We conducted a prospective, dose escalation (100, 200, and 300 mg·kg–1·day–1) safety study of bovine lactoferrin (Glanbia Nutritionals, USA) dissolved in sterile water (100 mg·mL–1) for 30 days in preterm infants with birth weight <1500 g. Safety related to adverse events (AEs), tolerability, and exposure-response of lactoferrin was assessed. We enrolled 31 patients [10, 10, and 11 patients, for the lactoferrin treatment groups (100, 200, and 300 mg·kg–1·day–1, respectively)] over a 10-month period. No AEs related to the study solution occurred, and lactoferrin was tolerated by each group. During lactoferrin supplementation, one bloodstream infection occurred in each group, but there were no incidences of urinary tract infections and no cases of necrotizing enterocolitis. Postnatal cytomegalovirus acquisition was detected in the group treated with 200 mg·kg–1·day–1 (n = 2). There were no adverse effects on hepatic, renal, or hematologic function. All of the patients survived to discharge. Bovine lactoferrin at doses up to 300 mg·kg–1·day–1 is safe in preterm infants. Future studies examining higher doses of lactoferrin, length of treatment, and potency of different products will aid in determining the optimal approach for the use of lactoferrin to prevent infections in preterm infants.

[Clinical guidelines for the diagnosis and treatment of neonatal necrotizing enterocolitis (2020)]

Necrotizing enterocolitis (NEC) is a devastating gastrointestinal disease of neonates, especially of preterm infants, with high morbidity and mortality. The surviving infants may have digestive tract and neurological sequelae. Therefore, the prevention and treatment of NEC are of great significance in improving survival rate and survival quality of neonates. To provide evidence-based recommendations for management of NEC, the guidelines were developed based on the Grading of Recommendations Assessment, Development and Evaluation (GRADE) and the current domestic and overseas studies.

Immunologic Properties of Human Milk and Clinical Implications in the Neonatal Population

Human milk contains various bioactive substances including hormones, immunoglobulins, enzymes, and growth factors in addition to its macro- and micronutrients. It has been suggested that human milk is a vehicle of communication between the maternal and infant immune systems, providing passive protection as well as direct active immunomodulation. Human milk protects newborns against pathogens by acting directly on multiple physiologic systems. Bioactive and immunologic factors regulate the infant's immune, metabolic, and microbiome systems. Breastfeeding protects infants in all socioeconomic groups, showing a pattern of protective dose/duration-response effects. This review summarizes the immune components and immunologic properties of human milk and provides an update of their potential implications in the neonatal population.

Enteral Bioactive Factor Supplementation in Preterm Infants: A Systematic Review

Feeding preterm infants with mother’s own milk is associated with a reduction in postnatal complications and an improved neurocognitive outcome. Therefore, the bioactive factor composition of human milk has been used as a tool for the development of nutritional supplements with a potential prophylactic or therapeutic effect. The aim of this systematic review was to provide an overview on bioactive factors which have been studied as supplement to enteral nutrition in randomized controlled trials, and to provide an overview of ongoing trials. MEDLINE, EMBASE, CENTRAL, and clinical trial registers were searched. Studies on the antimicrobial protein lactoferrin were excluded as these were summarized very recently in three separate systematic reviews. Studies on vitamins D, K and iron were also excluded as they are already incorporated in most international guidelines. We identified 17 different bioactive factors, which were investigated in 26 studies. Despite the encouraging potential effects of several bioactive factors, more high-quality studies with a sufficient number of preterm infants are required before a certain factor may be implemented into clinical practice. Three large trials (n > 500) that investigate the effects of either enteral insulin or vitamin A are currently ongoing and could provide more definite answers on these specific supplements.

Systemic and mucosal levels of lactoferrin in very low birth weight infants supplemented with bovine lactoferrin

Lactoferrin supplementation may help prevent infections in preterm infants, but the efficacy has varied with different doses and products. We assessed the absorption and excretion of bovine lactoferrin (bLF) in 31 infants receiving 100, 200, or 300 mg·kg^-1·day^-1 of enteral bLF for 30 days. bLF and human lactoferrin (hLF) in infant saliva, blood, urine, and stool, as well as expressed (EBM) or donor breast milk (DBM) that were collected (i) before the treatment was initiated, (ii) at study day 22, and (iii) one week after treatment cessation, were measured using ELISA. During treatment, bLF was absorbed from the gastrointestinal tract and detected in plasma, saliva, and urine, as well as excreted in stool. Levels of bLF in the saliva and stool began to decline within 12 h after dosing, and bLF was undetectable in all samples one week after treatment. The concentrations of hLF exceeded those of bLF across sample types and time-points. Infants receiving EBM demonstrated higher levels of hLF in the saliva and stool than those receiving DBM. Neither bLF nor hLF levels varied by patient characteristics, bLF dosage, or infection status. This is the first study demonstrating bLF absorption into the bloodstream and distribution to saliva and urine in preterm infants. Future studies should further explore LF pharmacokinetics because higher and more frequent dosing may improve the clinical benefit of LF supplementation.

Evidence from systematic reviews of randomized trials on enteral lactoferrin supplementation in preterm neonates

In this commentary, we summarize the current evidence from randomized controlled trials on enteral lactoferrin supplementation in preterm neonates. Our recently completed systematic review includes 12 randomized controlled trials performed all over the world. Our meta-analysis suggests clinical benefit in decreasing late-onset sepsis, late-onset fungal sepsis, length of stay in the hospital and urinary tract infections. There were no adverse effects. There was no statistically significant decrease in necrotizing enterocolitis, mortality or neurodevelopmental impairment in lactoferrin supplemented preterm infants. There was significant statistical heterogeneity in the effects of lactoferrin on late-onset sepsis between larger and smaller studies, which may reflect either small study biases, differences in the effectiveness, dose or duration of supplemental lactoferrin products, or differences in underlying population risk, or any or all of these.

Enteral lactoferrin supplementation for prevention of sepsis and necrotizing enterocolitis in preterm infants

BACKGROUND

Lactoferrin, a normal component of human colostrum and milk, can enhance host defenses and may be effective for prevention of sepsis and necrotizing enterocolitis (NEC) in preterm neonates.

OBJECTIVES

To assess the safety and effectiveness of lactoferrin supplementation to enteral feeds for prevention of sepsis and NEC in preterm neonates. Secondarily, we assessed the effects of lactoferrin supplementation to enteral feeds on the duration of positive-pressure ventilation, development of chronic lung disease (CLD) or periventricular leukomalacia (PVL), length of hospital stay to discharge among survivors, and adverse neurological outcomes at two years of age or later.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to update our search. We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2019, Issue 9), MEDLINE via PubMed (1966 to 20 January 2020), PREMEDLINE (1996 to 20 January 2020), Embase (1980 to 20 January 2020), and CINAHL (1982 to 20 January 2020). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomized controlled trials and quasi-randomized trials.

SELECTION CRITERIA

In our search, we included randomized controlled trials (RCTs) evaluating enteral lactoferrin supplementation at any dose or duration to prevent sepsis or NEC in preterm neonates.

DATA COLLECTION AND ANALYSIS

We used the standard methods of Cochrane Neonatal and the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

Meta-analysis of data from twelve randomized controlled trials showed that lactoferrin supplementation to enteral feeds decreased late-onset sepsis (typical RR 0.82, 95% CI 0.74 to 0.91; typical RD -0.04, 95% CI, -0.06, -0.02; NNTB 25, 95% CI 17 to 50; 12 studies, 5425 participants, low-certainty evidence) and decreased length of hospital stay (MD -2.38, 95% CI, -4.67, -0.09; 3 studies, 1079 participants, low-certainty evidence). Sensitivity analysis including only good methodological certainty studies suggested a decrease in late-onset sepsis with enteral lactoferrin supplementation (typical RR 0.87, 95% CI, 0.78, 0.97; typical RD -0.03, 95% CI, -0.05, -0.0; 9 studies, 4702 participants, low-certainty evidence). There were no differences in NEC stage II or III (typical RR 1.10, 95% CI, 0.86, 1.41; typical RD -0.00, 95% CI, -0.02, 0.01; 7 studies, 4874 participants; low-certainty evidence) or 'all-cause mortality' (typical RR 0.90, 95% CI 0.69, 1.17; typical RD -0.00, 95% CI, -0.01, 0.01; 11 studies, 5510 participants; moderate-certainty evidence). One study reported no differences in neurodevelopmental testing by Mullen's or Bayley III at 24 months of age after enteral lactoferrin supplementation (one study, 292 participants, low-certainty evidence). Lactoferrin supplementation to enteral feeds with probiotics decreased late-onset sepsis (RR 0.25, 95% CI 0.14 to 0.46; RD -0.13, 95% CI -0.18 to -0.08; NNTB 8, 95% CI 6 to 13; 3 studies, 564 participants; low-certainty evidence) and NEC stage II or III (RR 0.04, 95% CI 0.00 to 0.62; RD -0.05, 95% CI -0.08 to -0.03; NNTB 20, 95% CI 12.5 to 33.3; 1 study, 496 participants; very low-certainty evidence), but not 'all-cause mortality' (very low-certainty evidence). Lactoferrin supplementation to enteral feeds with or without probiotics had no effect on CLD, duration of mechanical ventilation or threshold retinopathy of prematurity (low-certainty evidence). Investigators reported no adverse effects in the included studies.

AUTHORS' CONCLUSIONS

We found low-certainty evidence from studies of good methodological quality that lactoferrin supplementation of enteral feeds decreases late-onset sepsis but not NEC ≥ stage II or 'all cause mortality' or neurodevelopmental outcomes at 24 months of age in preterm infants without adverse effects. Low- to very low-certainty evidence suggests that lactoferrin supplementation of enteral feeds in combination with probiotics decreases late-onset sepsis and NEC ≥ stage II in preterm infants without adverse effects, however, there were few included studies of poor methodological quality. The presence of publication bias and small studies of poor methodology that may inflate the effect size make recommendations for clinical practice difficult.

Lactoferrin Expression Is Not Associated with Late-Onset Sepsis in Very Preterm Infants

BACKGROUND

Preterm infants are at a high risk of developing late-onset sepsis (LOS). Lactoferrin is one of the most abundant endogenous antimicrobial proteins expressed in breast milk, stools, and blood, and a candidate for preventive intervention. Large clinical trials have recently investigated whether enteral supplementation with bovine lactoferrin reduces LOS.

AIM

To characterize lactoferrin levels in preterm infants with and without LOS during the first month of life.

METHODS

Very preterm and term infants were recruited and serial biosamples collected during the first month of life. Lactoferrin levels were determined by immunoassay in cord blood and peripheral blood on days 1, 7, 14, 21, and 28; in the stools on days 1 and 28; and in the mother's breast milk on days 7 and 21. Furthermore, we assessed the capacity of the peripheral blood to release lactoferrin in response to an in vitro challenge with live Staphylococcus epidermidis, lipopolysaccharide, and fibroblast-stimulating lipopeptide 1.

RESULTS

Plasma lactoferrin levels were higher in cord blood and day 1 peripheral blood and declined during the first month of life. Plasma lactoferrin levels were similar in term infants and in preterm infants with (n = 32) and without LOS (n = 53). S. epidermidis-induced lactoferrin levels were lower following the sepsis episode.

CONCLUSIONS

Endogenous lactoferrin expression in preterm infants does not appear to affect their risk of developing LOS. These findings are in line with the lack of benefit recently observed in large trials of enteral supplementation with bovine lactoferrin to prevent LOS.