Effects of lactoferrin on neonatal pathogens and Bifidobacterium breve in human breast milk

Lactoferrin deficiency during lactation increases the risk of depressive-like behavior in adult mice

BACKGROUND

Lactoferrin is an active protein in breast milk that plays an important role in the growth and development of infants and is implicated as a neuroprotective agent. The incidence of depression is currently increasing, and it is unclear whether the lack of lactoferrin during lactation affects the incidence of depressive-like behavior in adulthood.

RESULTS

Lack of lactoferrin feeding during lactation affected the barrier and innate immune functions of the intestine, disrupted the intestinal microflora, and led to neuroimmune dysfunction and neurodevelopmental delay in the hippocampus. When exposed to external stimulation, adult lactoferrin feeding-deficient mice presented with worse depression-like symptoms; the mechanisms involved were activation of the LPS-TLR4 signalling pathway in the intestine and hippocampus, reduced BDNF-CREB signaling pathway in hippocampus, increased abundance of depression-related bacteria, and decreased abundance of beneficial bacteria.

CONCLUSIONS

Overall, our findings reveal that lactoferrin feeding deficient during lactation can increase the risk of depressive-like behavior in adults. The mechanism is related to the regulatory effect of lactoferrin on the development of the "microbial-intestinal-brain" axis.

Isolation and Characterization of Cow-, Buffalo-, Sheep- and Goat-Milk-Derived Extracellular Vesicles

Milk is a complex biological fluid that has high-quality proteins including growth factors and also contains extracellular vesicles (EVs). EVs are a lipid bilayer containing vesicles that contain proteins, metabolites and nucleic acids. Several studies have proposed that EVs in cow milk can survive the gut and can illicit cross-species communication in the consuming host organism. In this study, we isolated and characterized extracellular vesicles from the raw milk of the four species of the Bovidae family, namely cow, sheep, goat and buffalo, that contribute 99% of the total milk consumed globally. A comparative proteomic analysis of these vesicles was performed to pinpoint their potential functional role in health and disease. Vesicles sourced from buffalo and cow milk were particularly enriched with proteins implicated in modulating the immune system. Furthermore, functional studies were performed to determine the anti-cancer effects of these vesicles. The data obtained revealed that buffalo-milk-derived EVs induced significantly higher cell death in colon cancer cells. Overall, the results from this study highlight the potent immunoregulatory and anti-cancer nature of EVs derived from the milk of Bovidae family members.

Lactoferrin, Osteopontin and Lactoferrin–Osteopontin Complex: A Critical Look on Their Role in Perinatal Period and Cardiometabolic Disorders

Milk-derived bioactive proteins have increasingly gained attention and consideration throughout the world due to their high-quality amino acids and multiple health-promoting attributes. Apparently, being at the forefront of functional foods, these bioactive proteins are also suggested as potential alternatives for the management of various complex diseases. In this review, we will focus on lactoferrin (LF) and osteopontin (OPN), two multifunctional dairy proteins, as well as to their naturally occurring bioactive LF–OPN complex. While describing their wide variety of physiological, biochemical, and nutritional functionalities, we will emphasize their specific roles in the perinatal period. Afterwards, we will evaluate their ability to control oxidative stress, inflammation, gut mucosal barrier, and intestinal microbiota in link with cardiometabolic disorders (CMD) (obesity, insulin resistance, dyslipidemia, and hypertension) and associated complications (diabetes and atherosclerosis). This review will not only attempt to highlight the mechanisms of action, but it will critically discuss the potential therapeutic applications of the underlined bioactive proteins in CMD.

Exploring the Potential of Human Milk and Formula Milk on Infants’ Gut and Health

Early-life gut microbiota plays a role in determining the health and risk of developing diseases in later life. Various perinatal factors have been shown to contribute to the development and establishment of infant gut microbiota. One of the important factors influencing the infant gut microbial colonization and composition is the mode of infant feeding. While infant formula milk has been designed to resemble human milk as much as possible, the gut microbiome of infants who receive formula milk differs from that of infants who are fed human milk. A diverse microbial population in human milk and the microbes seed the infant gut microbiome. Human milk contains nutritional components that promote infant growth and bioactive components, such as human milk oligosaccharides, lactoferrin, and immunoglobulins, which contribute to immunological development. In an attempt to encourage the formation of a healthy gut microbiome comparable to that of a breastfed infant, manufacturers often supplement infant formula with prebiotics or probiotics, which are known to have a bifidogenic effect and can modulate the immune system. This review aims to elucidate the roles of human milk and formula milk on infants’ gut and health.

Interaction of Pelargonium sidoides Compounds with Lactoferrin and SARS-CoV-2: Insights from Molecular Simulations

(1) Background: Pelargonium sidoides extracts and lactoferrin are two important natural, anti-inflammatory, and antiviral agents, which can interfere with the early stages of SARS-CoV-2 infection. Molecular docking and molecular dynamics simulation approaches have been applied to check for the occurrence of interactions of the Pelargonium sidoides compounds with lactoferrin and with SARS-CoV-2 components. (2) Methods: Computational methods have been applied to confirm the hypothesis of a direct interaction between PEL compounds and the lactoferrin protein and between Pelargonium sidoides compounds and SARS-CoV-2 Spike, 3CLPro, RdRp proteins, and membrane. Selected high-score complexes were structurally investigated through classical molecular dynamics simulation, while the interaction energies were evaluated using the molecular mechanics energies combined with generalized Born and surface area continuum solvation method. (3) Results: Computational analyses suggested that Pelargonium sidoides extracts can interact with lactoferrin without altering its structural and dynamical properties. Furthermore, Pelargonium sidoides compounds should have the ability to interfere with the Spike glycoprotein, the 3CLPro, and the lipid membrane, probably affecting the functional properties of the proteins inserted in the double layer. (4) Conclusion: Our findings suggest that Pelargonium sidoides may interfere with the mechanism of infection of SARS-CoV-2, especially in the early stages.

Lactoferrin and Human Neutrophil Protein (HNP) 1-3 Levels During the Neonatal Period in Preterm Infants

Antimicrobial polypeptides (APPs) are part of the innate immune system, but their specific role in the context of preterm birth is not yet understood. The aim of this investigation was to determine the systemic expression of APPs, i.e., lactoferrin (LF) and human neutrophil protein (HNP) 1-3 in preterm infants in the period of highest vulnerability for infection and to correlate these biomarkers with short-term outcome. We therefore conducted a prospective two-center study including plasma samples of 278 preterm infants and 78 corresponding mothers. APP levels were analyzed on day 1, 3, 7, and 21 of life via enzyme-linked immunosorbent assay (ELISA). The levels of LF and HNP1-3 remained stable during the first 21 days of life and were not influenced by maternal levels. Elevated APP levels were found at day 1 in infants born to mothers with amniotic infection syndrome (AIS vs. no AIS, mean ± SD in ng/ml: LF 199.8 ± 300 vs. 124.1 ± 216.8, HNP 1-3 16,819 ± 36,124 vs. 8,701 ± 11,840; p = 0.021, n = 179). We found no elevated levels of APPs before the onset of sepsis episodes or in association with other short-term outcomes that are in part mediated by inflammation such as necrotizing enterocolitis (NEC) or retinopathy of prematurity (ROP). Interestingly, infants developing bronchopulmonary dysplasia (BPD) showed higher levels of HNP1-3 on day 21 than infants without BPD (13,473 ± 16,135 vs. 8,388 ± 15,938, n = 111, p = 0.008). In infants born without amniotic infection, levels of the measured APPs correlated with gestational age and birth weight. In our longitudinal study, systemic levels of LF and HNP 1-3 were not associated with postnatal infection and adverse short-term outcomes in preterm infants.

A Review on Lactoferrin and Central Nervous System Diseases

Central nervous system (CNS) diseases are currently one of the major health issues around the world. Most CNS disorders are characterized by high oxidative stress levels and intense inflammatory responses in affected tissues. Lactoferrin (Lf), a multifunctional iron-binding glycoprotein, plays a significant role in anti-inflammatory, antibacterial, antiviral, reactive oxygen species (ROS) modulator, antitumor immunity, and anti-apoptotic processes. Previous studies have shown that Lf is abnormally expressed in a variety of neurological diseases, especially neurodegenerative diseases. Recently, the promotion of neurodevelopment and neuroprotection by Lf has attracted widespread attention, and Lf could be exploited both as an active therapeutic agent and drug nanocarrier. However, our understanding of the roles of Lf proteins in the initiation or progression of CNS diseases is limited, especially the roles of Lf in regulating neurogenesis. This review highlights recent advances in the understanding of the major pharmacological effects of Lf in CNS diseases, including neurodegenerative diseases, cerebrovascular disease, developmental delays in children, and brain tumors.

Lactoferrin Against SARS-CoV-2: In Vitro and In Silico Evidences

Lactoferrin (Lf) is a cationic glycoprotein synthetized by exocrine glands and is present in all human secretions. It is also secreted by neutrophils in infection and inflammation sites. This glycoprotein possesses antimicrobial activity due to its capability to chelate two ferric ions per molecule, as well as to interact with bacterial and viral anionic surface components. The cationic features of Lf bind to cells, protecting the host from bacterial and viral injuries. Its anti-inflammatory activity is mediated by the ability to enter inside the nucleus of host cells, thus inhibiting the synthesis of proinflammatory cytokine genes. In particular, Lf down-regulates the synthesis of IL-6, which is involved in iron homeostasis disorders and leads to intracellular iron overload, favoring viral replication and infection. The well-known antiviral activity of Lf has been demonstrated against DNA, RNA, and enveloped and naked viruses and, therefore, Lf could be efficient in counteracting also SARS-CoV-2 infection. For this purpose, we performed in vitro assays, proving that Lf exerts an antiviral activity against SARS-COV-2 through direct attachment to both SARS-CoV-2 and cell surface components. This activity varied according to concentration (100/500 μg/ml), multiplicity of infection (0.1/0.01), and cell type (Vero E6/Caco-2 cells). Interestingly, the in silico results strongly supported the hypothesis of a direct recognition between Lf and the spike S glycoprotein, which can thus hinder viral entry into the cells. These in vitro observations led us to speculate a potential supplementary role of Lf in the management of COVID-19 patients.

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..

The impact of thermal processing on the simulated infant gastrointestinal digestion, bactericidal and anti-inflammatory activity of bovine lactoferrin - An in vitro study

Lactoferrin (LF) is a multifunctional glycoprotein which, when thermally processed, undergoes significant physicochemical changes. The link between such changes and the bioactivity of LF is not well characterised and requires much research. In this work, bovine LF solutions (1%, w/v, protein, pH 7) were thermally processed using high temperature short time conditions (72, 80, 85 or 95 °C with 15 s holding times). Following this, it was shown that LF and heat induced LF aggregates were largely resistant to simulated infant gastric, but not intestinal, digestion. Also, the efficacy of LF bactericidal activity, and inhibition of lipopolysaccharide-induced NF-κB activation were negatively impacted by thermal processing. This study confirmed that the efficacy of LF bio-functionalities was affected by the extent of heat-induced changes in protein structure whereby processing conditions of least severity (i.e. pasteurisation) had the least impact on bioactivity.

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.

Role of Human Milk Bioactives on Infants' Gut and Immune Health

Exclusive human milk feeding of the newborn is recommended during the first 6 months of life to promote optimal health outcomes during early life and beyond. Human milk contains a variety of bioactive factors such as hormones, cytokines, leukocytes, immunoglobulins, lactoferrin, lysozyme, stem cells, human milk oligosaccharides (HMOs), microbiota, and microRNAs. Recent findings highlighted the potential importance of adding HMOs into infant formula for their roles in enhancing host defense mechanisms in neonates. Therefore, understanding the roles of human milk bioactive factors on immune function is critical to build the scientific evidence base around breastfeeding recommendations, and to enhance positive health outcomes in formula fed infants through modifications to formulas. However, there are still knowledge gaps concerning the roles of different milk components, the interactions between the different components, and the mechanisms behind health outcomes are poorly understood. This review aims to show the current knowledge about HMOs, milk microbiota, immunoglobulins, lactoferrin, and milk microRNAs (miRNAs) and how these could have similar mechanisms of regulating gut and microbiota function. It will also highlight the knowledge gaps for future research.

Iron supplementation and iron-fortified foods: a review

About one-third of the world population is suffering from iron deficiency. Delivery of iron through diet is a practical, economical, and sustainable approach. Clinical studies have shown that the consumption of iron-fortified foods is one of the most effective methods for the prevention of iron deficiency. However, supplementing iron through diet can cause undesirable side-effects. Thus, it is essential to develop new iron-rich ingredients, iron-fortified products with high bioavailability, better stability, and lower cost. It is also essential to develop newer processing technologies for more effective fortification. This review compared the iron supplementation strategies used to treat the highly iron-deficient population and the general public. We also reviewed the efficacy of functional (iron-rich) ingredients that can be incorporated into food materials to produce iron-fortified foods. The most commonly available foods, such as cereals, bakery products, dairy products, beverages, and condiments are still the best vehicles for iron fortification and delivery.Scope of reviewThe manuscript aims at providing a comprehensive review of the latest publications that cover three aspects: administration routes for iron supplementation, iron-rich ingredients used for iron supplementation, and iron-fortified foods.

A Single Plasmid of Nisin-Controlled Bovine and Human Lactoferrin Expressing Elevated Antibacterial Activity of Lactoferrin-Resistant Probiotic Strains

Lactoferrin (LF) is a multifunctional protein found in mammals, and it shows broad-spectrum antimicrobial activity. To improve the functional properties of specific probiotics in order to provide both the beneficial characteristics of lactic acid bacteria and the biological activity of LF, cDNAs of bovine LF (BLF), human LF (HLF), or porcine LF (PLF) were cloned into a nisin-inducible plasmid. These were then transformed into the selected eight probiotics, which are LF-resistant hosts. Expression of recombinant LFs (rLFs) was analyzed via SDS-PAGE and Western blot analysis. Although the selected host strains may not contain the nisRK genes (NisK, the sensor kinase; NisR, the regulator protein), the components of autoregulation, a low level of LFs expression can be successfully induced by using nisin within bacterial cells in a time-dependent manner in three engineered clones, including Lactobacillus delbrueckii/HLF, L. delbrueckii/BLF, and L. gasseri/BLF. Lactobacillus delbrueckii and Lactobacillus gasseri originate from yogurt and human milk, respectively, and both strains are functional probiotic strains. Therefore, we further compared the antibacterial activities of disrupted recombinant probiotic clones, conventional strains (host control), and vector control ones by using agar diffusion and broth inhibition analysis, and the expression of rLFs in the above three clones considerately improved their antibacterial efficacies against four important food-borne pathogens, namely, Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, and Salmonellaenterica. In conclusion, this study provides a simple strategy for the production of functional LFs (BLF and HLF) in both functional and LF-resistant hosts for applications in the field.

Clinical Outcomes of Single vs. Two-Strain Probiotic Prophylaxis for Prevention of Necrotizing Enterocolitis in Preterm Infants

Background: The administration of live microbiota (probiotic) via enteral route to preterm infants facilitates intestinal colonization with beneficial bacteria, resulting in competitive inhibition of the growth of pathogenic bacteria preventing gut microbiome dysbiosis. This dysbiosis is linked to the pathogenesis of necrotizing enterocolitis (NEC), an acquired multi-factorial intestinal disease characterized by microbial invasion of the gut mucosa, particularly affecting preterm infants. Probiotic prophylaxis reduces NEC; however, variations in strain-specific probiotic effects, differences in administration protocols, and synergistic interactions with the use of combination strains have all led to challenges in selecting the optimal probiotic for clinical use. Aim: To compare any differences in NEC rates, feeding outcomes, co-morbidities in preterm infants receiving single or two-strain probiotics over a 4-year period. The two-strain probiotic prophylaxis was sequentially switched over after 2 years to the single strain probiotic within this 4-year study period, in similar cohort of preterm infants. Methods: During two consecutive equal 2-year epochs, preterm infants (<32 weeks and or with birth weight <1,500 g) receiving two-strain (Lactobacillus acidophilus and Bifidobacterium bifidum) and single strain (Bifidobacterium breve M-16 V,) probiotic prophylaxis for prevention of NEC were included in this retrospective, observational study. The primary outcome included rates of NEC; secondary outcomes included prematurity related co-morbidities and feeding outcomes. Time to reach full enteral feeds was identified as the first day of introducing milk feeds at 150 ml/kg/day. Results: There were 180 preterm infants in the two-strain, 196 in the single strain group from the two equal consecutive 2-year epochs. There were no differences in the NEC rates, feeding outcomes, all-cause morbidities except for differences in rates of retinopathy of prematurity. Conclusion: In our intensive-care setting, clinical outcomes of single vs. two-strain probiotic prophylaxis for prevention of NEC were similar. Although our study demonstrates single strain probiotic may be equally effective than two-strain in the prevention of NEC, small sample size and low baseline incidence of NEC in our unit were not sufficiently powered to compare single vs. two-strain probiotic prophylaxis in preventing NEC. Further clustered randomized controlled trials are required to study the effects of single vs. multi-strain probiotic products for NEC prevention in preterm infants.

Fortification With Bovine Colostrum Enhances Antibacterial Activity of Human Milk

Objectives

Human milk (HM) is the optimal diet for neonates, but it does not provide enough nutrients for preterm infants. HM fortifiers based on highly processed mature bovine milk (BMFs) are routinely used for preterm infants despite risks of causing gut dysfunction and systemic infection. Gently‐processed bovine colostrum as a fortifier (BCF) may better protect against infection and inflammation. We hypothesized that BCF‐fortified HM has enhanced antimicrobial activity against pathogens that commonly cause neonatal sepsis, relative to BMF‐fortified HM.

Methods

Holder‐pasteurized HM samples (10 mothers) were aliquoted into 3 fractions: unfortified HM and HM fortified with either BMF or BCF. The samples were analyzed for pH, lactoferrin concentrations, and antimicrobial activities against Staphylococcus epidermidis, Escherichia coli, and Enterococcus faecalis.

Results

HM+BCF had a lower pH and higher lactoferrin levels than HM+BMF, with HM being intermediate. Relative to infant formula, HM decreased the growth of S epidermidis, E coli, and E faecalis, with no difference between preterm and term HM. Addition of BMF abolished the antimicrobial effect of HM against S epidermidis and E faecalis but not E coli. By contrast, addition of BCF into HM enhanced antimicrobial activity against S epidermidis and E coli, relative to unfortified HM. HM+BCF was superior to HM+BMF in inhibiting growth of all tested bacteria.

Conclusion

BMF fortification decreased whereas BCF fortification enhanced in vitro antimicrobial activity of HM. This effect may partly be derived from the high levels of antimicrobial factors found in BCF, including lactoferrin. BCF may be a better fortifier than BMF for preterm infants.

COVID-19 during Pregnancy and Postpartum

As the COVID-19 pandemic intensified the global health crisis, the containment of SARS-CoV-2 infection in pregnancies, and the inherent risk of vertical transmission of virus from mother-to-fetus (or neonate) poses a major concern. Most COVID-19-Pregnancy patients showed mild to moderate COVID-19 pneumonia with no pregnancy loss and no congenital transmission of the virus; however, an increase in hypoxia-induced preterm deliveries was apparent. Also, the breastmilk of several mothers with COVID-19 tested negative for the virus. Taken together, the natural barrier function during pregnancy and postpartum seems to deter the SARS-CoV-2 transmission from mother-to-child. This clinical observation warrants to explore the maternal-fetal interface and identify the innate defense factors for prevention and control of COVID-19-Pregnancy. Lactoferrin (LF) is a potent antiviral iron-binding protein present in the maternal-fetal interface. In concert with immune co-factors, maternal-LF modulates chemokine release and lymphocyte migration and amplify host defense during pregnancy. LF levels during pregnancy may resolve hypertension via down-regulation of ACE2; consequently, may limit the membrane receptor access to SARS-CoV-2 for cellular entry. Furthermore, an LF-derived peptide (LRPVAA) has been shown to block ACE receptor activity in vitro. LF may also reduce viral docking and entry into host cells and limit the early phase of COVID-19 infection. An in-depth understanding of LF and other soluble mammalian milk-derived innate antiviral factors may provide insights to reduce co-morbidities and vertical transmission of SARS-CoV-2 infection and may lead to the development of effective nutraceutical supplements.

The Role of Human Milk in Decreasing Necrotizing Enterocolitis Through Modulation of the Infant Gut Microbiome: A Scoping Review

BACKGROUND

Necrotizing enterocolitis is associated with a high incidence of morbidity and mortality in premature infants. Human milk minimizes necrotizing enterocolitis risk, although the mechanism of protection is not thoroughly understood. Increasingly, dysbiosis of the infant gut microbiome, which is affected by infant diet, is hypothesized to play a role in necrotizing enterocolitis pathophysiology.

RESEARCH AIM

The aim of this scoping review was to summarize the state of the science regarding the hypothesis that the gut microbiome composition is a mediator of the relationship between human milk and decreased incidence of necrotizing enterocolitis within a sample of human infants.

METHODS

Electronic databases and reference lists were searched for peer-reviewed primary research articles addressing the link between human milk, gut microbiome composition, and subsequent incidence of necrotizing enterocolitis among human infants.

RESULTS

A total of four studies met criteria for inclusion in this review. Of these, evidence supporting the link between human milk, gut microbiome composition, and necrotizing enterocolitis was found in two (50%) studies.

CONCLUSION

Some evidence linking all three variables is provided in this review. Given the small number of available studies, and the limitations of those studies, more research is urgently needed to thoroughly understand the protection against necrotizing enterocolitis gained through the provision of human milk.

Lactoferrin Metal Saturation-Which Form Is the Best for Neonatal Nutrition?

We evaluated the impact of metal saturation of lactoferrin (with iron and manganese) on population numbers of pathogenic species relevant for neonatal sepsis that commonly originates from the gut due to bacterial translocation. Little attention has been paid to how metal ions bound to the protein affect its activity. Several reference and clinical strains as well as probiotic strains were incubated with different forms of lactoferrin: metal-depleted (apolactoferrin), iron-saturated (hololactoferrin) and manganese-saturated lactoferrin. We also attempted to confirm the observed effects of lactoferrin forms in vivo using rat pups. The observed decrease in population numbers of Gram-negative rods could not be confirmed by quantitative plating—lactoferrin may regulate these populations diversely (e.g., by anti-biofilm activity) and contribute to the inhibition of inflammatory response. We did not see any effect of lactoferrin forms on staphylococci and bifidobacteria. However, we have noted a significant increase of population numbers of Lactobacillus strains upon incubation with manganese-saturated lactoferrin. These results were confirmed in vivo in a rat model. Metal saturation is an underestimated factor regulating lactoferrin activity. Some forms are more potent in the inhibition of pathogenic species while others, such as manganese-saturated lactoferrin, could contribute to the restoration of gut homeostasis.

ELFIN, the United Kingdom preterm lactoferrin trial: interpretation and future questions 1

Results from previous studies have suggested that supplemental bovine lactoferrin (BLF) given to preterm infants (<32 weeks gestation) reduces late-onset sepsis (LOS) and necrotising enterocolitis (NEC). The Enteral Lactoferrin in Neonates (ELFIN) study, performed in the UK, aimed to further address this issue with a well powered double-blind placebo controlled trial of >2200 preterm infants. The results from ELFIN did not demonstrate a reduction in LOS or NEC, or several other clinically important measures. Of the 1093 infants, 316 (29%) in the intervention group developed late-onset sepsis versus 334 (31%) of 1089 in the control group, with an adjusted risk ratio of 0.95 (95% CI = 0.86-1.04; p = 0.233). Reasons for the differences in ELFIN trial results and other studies may include population differences, the routine use of antifungal prophylaxis in the UK, timing of administration of the lactoferrin in relation to disease onset, or specific properties of the lactoferrin used in the different trials. The UK National Institutes for Health Research funded "Mechanisms Affecting the Guts of Preterm Infants in Enteral feeding trials" (MAGPIE) study is further exploring the use of lactoferrin, and the results should be available soon.

The Biology of Lactoferrin, an Iron-Binding Protein That Can Help Defend Against Viruses and Bacteria

Lactoferrin is a nutrient classically found in mammalian milk. It binds iron and is transferred via a variety of receptors into and between cells, serum, bile, and cerebrospinal fluid. It has important immunological properties, and is both antibacterial and antiviral. In particular, there is evidence that it can bind to at least some of the receptors used by coronaviruses and thereby block their entry. Of importance are Heparan Sulfate Proteoglycans (HSPGs) and the host receptor angiotensin-converting enzyme 2 (ACE2), as based on other activities lactoferrin might prevent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from attaching to the host cells. Lactoferrin (and more specifically enteric-coated LF because of increased bioavailability) may consequently be of preventive and therapeutic value during the present COVID-19 pandemic.

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

BACKGROUND

Very low birthweight or preterm infants are at increased risk of adverse outcomes including sepsis, necrotising enterocolitis, and death. We assessed whether supplementing the enteral diet of very low-birthweight infants with lactoferrin, an antimicrobial protein, reduces all-cause mortality or major morbidity.

METHODS

We did a multicentre, double-blind, pragmatic, randomised superiority trial in 14 Australian and two New Zealand neonatal intensive care units. Infants born weighing less than 1500 g and aged less than 8 days, were eligible and randomly assigned (1:1) using minimising web-based randomisation to receive once daily 200 mg/kg pasteurised bovine lactoferrin supplements or no lactoferrin supplement added to breast or formula milk until 34 weeks' post-menstrual age (or for 2 weeks, if longer), or until discharge from the study hospital if that occurred first. Designated nurses preparing the daily feeds were not masked to group assignment, but other nurses, doctors, parents, caregivers, and investigators were unaware. The primary outcome was survival to hospital discharge or major morbidity (defined as brain injury, necrotising enterocolitis, late-onset sepsis at 36 weeks' post-menstrual age, or retinopathy treated before discharge) assessed in the intention-to-treat population. Safety analyses were by treatment received. We also did a prespecified, PRISMA-compliant meta-analysis, which included this study and other relevant randomised controlled trials, to estimate more precisely the effects of lactoferrin supplementation on late-onset sepsis, necrotising enterocolitis, and survival. This trial is registered with the Australian and New Zealand Clinical Trials Registry, ACTRN12611000247976.

FINDINGS

Between June 27, 2014, and Sept 1, 2017, we recruited 1542 infants; 771 were assigned to the intervention group and 771 to the control group. One infant who had consent withdrawn before beginning lactoferrin treatment was excluded from analysis. In-hospital death or major morbidity occurred in 162 (21%) of 770 infants in the intervention group and in 170 (22%) of 771 infants in the control group (relative risk [RR] 0·95, 95% CI 0·79-1·14; p=0·60). Three suspected unexpected serious adverse reactions occurred; two in the lactoferrin group, namely unexplained late jaundice and inspissated milk syndrome, but were not attributed to the intervention and one in the control group had fatal inspissated milk syndrome. Our meta-analysis identified 13 trials completed before Feb 18, 2020, including this Article, in 5609 preterm infants. Lactoferrin supplements significantly reduced late-onset sepsis (RR 0·79, 95% CI 0·71-0·88; p<0·0001; I²=58%), but not necrotising enterocolitis or all-cause mortality.

INTERPRETATION

Lactoferrin supplementation did not improve death or major morbidity in this trial, but might reduce late-onset sepsis, as found in our meta-analysis of over 5000 infants. Future collaborative studies should use products with demonstrated biological activity, be large enough to detect moderate and clinically important effects reliably, and assess greater doses of lactoferrin in infants at increased risk, such as those not exclusively receiving breastmilk or infants of extremely low birthweight.

FUNDING

Australian National Health and Medical Research Council.

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.

Adjunctive therapy to treat neonatal sepsis

Introduction: Neonatal sepsis (NS) is a very severe condition that causes significant morbidity and mortality.Areas covered: To overcome the limits of antibiotic therapy and improve NS outcomes, measures chosen among those theoretically able to improve host defenses or positively interfere with deleterious immune responses could be suggested. This paper discusses the mechanisms of action of these measures, whether their efficacy in prophylaxis justifies use in NS therapy and their impact.Expert opinion: NS remains a relevant problem despite the availability of antibiotics effective against the most common agents and the introduction of effective preventive measures such as group B Streptococcus prenatal screening and intrapartum antibiotic prophylaxis. This explains why attempts to introduce new prophylactic and therapeutic measures have been made. Unfortunately, none of the measures suggested and tested to date can be considered a definitive advance. It is highly likely that in the future, new measures will be proposed according to the increase in the knowledge of the characteristics of immune system function in preterm infants and the methods to modulate unproper immune responses.

Lactoferrin in Human Milk of Prolonged Lactation

Among the immunologically important bioactive factors present in human milk, lactoferrin (Lf) has emerged as a key player with wide-ranging features that directly and indirectly protect the neonate against infection caused by a variety of pathogens. The concentration of Lf in human milk is lactation-stage related; colostrum contains more than 5 g/L, which then significantly decreases to 2–3 g/L in mature milk. The milk of mothers who are breastfeeding for more than one year is of a standard value, containing macronutrients in a composition similar to that of human milk at later stages. The aim of this study was to evaluate lactoferrin concentration in prolonged lactation from the first to the 48th month postpartum. Lactating women (n = 120) up to 48 months postpartum were recruited to the study. The mean value of lactoferrin concentration was the lowest in the group of 1–12 months of lactation (3.39 ± 1.43 g/L), significantly increasing in the 13–18 months group (5.55 ± 4.00 g/L; p < 0.006), and remaining at a comparable level in the groups of 19–24 month and over 24 months (5.02 ± 2.97 and 4.90 ± 3.18 g/L, respectively). The concentration of lactoferrin in mother’s milk also showed a positive correlation with protein concentration over lactation from the first to the 48th month (r = 0.3374; p = 0.0002). Our results demonstrate the high immunology potential of human milk during prolonged lactation and that Lf concentration is close to the Lf concentration in colostrum. Evidence of stable or rising immunoprotein levels during prolonged lactation provides an argument for foregoing weaning; however, breastfeeding must be combined with solid foods meet the new requirements of a rapidly growing six-month or older baby.

The Impact of Lactoferrin on the Growth of Intestinal Inhabitant Bacteria

Lactoferrin (Lf) is an iron-binding milk glycoprotein that promotes the growth of selected probiotic strains. The effect of Lf on the growth and diversification of intestinal microbiota may have an impact on several issues, including (i) strengthening the permeability of the epithelial cell monolayer, (ii) favoring the microbial antagonism that discourages the colonization and proliferation of enteric pathogens, (iii) enhancing the growth and maturation of cell-monolayer components and gut nerve fibers, and (iv) providing signals to balance the anti- and pro-inflammatory responses resulting in gut homeostasis. Given the beneficial role of probiotics, this contribution aims to review the current properties of bovine and human Lf and their derivatives in in vitro probiotic growth and Lf interplay with microbiota described in the piglet model. By using Lf as a component in pharmacological products, we may enable novel strategies that promote probiotic growth while conferring antimicrobial activity against multidrug-resistant microorganisms that cause life-threatening diseases, especially in neonates.

[A review on the relationship between breast milk nutrients and brain development in preterm infants]

Breast milk is the preferred food for preterm infants. In recent years, the role of breast milk in the brain development of preterm infants has attracted more and more attention. Studies have shown that the effect of breastfeeding on neurodevelopment and long-term cognitive outcome of preterm infants may persist into childhood, adolescence, and even adulthood. The nutrients in breast milk, such as oligosaccharides, polyunsaturated fatty acids, and lactoferrin, play an important role in this process. This article reviews the latest research advances in the role of breast milk nutrients in the brain development of preterm infants and elaborates on the concept and function of each nutrient.

Lactoferrin: A Critical Player in Neonatal Host Defense

Newborn infants are at a high risk for infection due to an under-developed immune system, and human milk has been shown to exhibit substantial anti-infective properties that serve to bolster neonatal defenses against multiple infections. Lactoferrin is the dominant whey protein in human milk and has been demonstrated to perform a wide array of antimicrobial and immunomodulatory functions and play a critical role in protecting the newborn infant from infection. This review summarizes data describing the structure and important functions performed by lactoferrin in protecting the neonate from infection and contributing to the maturation of the newborn innate and adaptive immune systems. We also briefly discuss clinical trials examining the utility of lactoferrin supplementation in the prevention of sepsis and necrotizing enterocolitis in newborn infants. The data reviewed provide rationale for the continuation of studies to examine the effects of lactoferrin administration on the prevention of sepsis in the neonate.