Assessment of bioactivities of the human milk lactoferrin–osteopontin complex in vitro

Milk osteopontin has high iron-binding capacity and facilitates iron absorption in intestinal cells

Insufficient absorption of iron and the consequent development of iron deficiency have serious health consequences. Hence, identification and development of iron delivery systems that can increase the bioavailability and uptake of dietary iron are important. Osteopontin (OPN) is an acidic and highly phosphorylated integrin-binding protein found in milk where it exists as a full-length protein and as N-terminally derived fragments. Milk OPN can be taken up by enterocytes and transported across the intestinal barrier into the circulation. Milk OPN has previously been shown to bind calcium and magnesium. This study investigates milk OPN as a carrier of iron and its potential to increase iron absorption in intestinal cells. Full-length OPN and N-terminal fragments of OPN were shown to bind ∼30 and ∼10 mol of iron, respectively, and the phosphorylated residues were crucial for iron binding. Osteopontin retained iron bound after simulated gastrointestinal digestion. Immunodetection of digested OPN and OPN-Fe complexes showed that the OPN-Fe complexes were more resistant to pepsin digestion than OPN without bound iron. The cellular uptake of iron was investigated by measuring intracellular ferritin formation and mRNA expression of divalent metal transporter 1 in Caco-2 cells. Osteopontin increased the uptake of iron even in the presence of phytic acid, a dietary inhibitor of iron absorption. These data indicate that OPN can function as an iron carrier for use in alternative strategies for delivering iron in a bioavailable form for intestinal uptake.

Enrichment of low-abundance osteopontin in bovine milk via reciprocating free-flow isoelectric focusing

Osteopontin (OPN) in milk plays an important role in intestinal and brain development in early infancy, and great attention has been focused on OPN isolation to add extra OPN in infant formula. However, large-scale OPN isolation is limited by the low efficiency of sample pretreatment. Herein, we utilized preparative reciprocating free-flow isoelectric focusing (RFFIEF) to showcase the enrichment of low-abundance OPN in bovine milk, which contained an extremely high concentration of unwanted proteins. The reciprocating IEF format and the design of the multi-channel collector allowed us to enrich OPN in 1 L milk within 6 h. We removed 97.5% of unwanted proteins and obtained an enrichment factor of 11. Thus, our RFFIEF method can be applied to the preparative pretreatment of the large-scale milk sample and potentially improve the efficiency of downstream OPN purification.

Lactoferrin-Based Heteroprotein Systems, From Their Formation Mechanism, Properties, To Applications

Lactoferrin (LF) is an important iron-binding glycoprotein found in milk and mucosal secretions. The alkaline lactoferrin can interact with some acidic proteins to form heteroprotein systems with multifunctional properties and a wide range of applications. Lactoferrin can interact with animal and plant proteins mainly through the electrostatic forces, dipolar attraction, and hydrophobic interactions. In this review, the types of heteroprotein complexes formed by the complex coacervation of lactoferrin with other proteins are introduced, including the preparation, structure, and applications. The factors affecting the formation of heteroprotein complexes are described, such as pH, ionic strength, mixing ratio, total protein concentration, and temperature. The issues and challenges in the formation of heteroprotein complexes are also discussed.

The impact of complexation or complex coacervation of lactoferrin and osteopontin on simulated infant gastrointestinal digestion, intestinal inflammation, and in vivo bone development

Lactoferrin (LF) and osteopontin (OPN) are bioactive milk proteins which can form heteroprotein complexes and complex coacervates. This research studied the effect of LF-OPN complexation and complex coacervation on the simulated infant gastrointestinal digestion of LF with subsequent examination of gut and bone health bioactivities in preclinical models. In an infant digestion model, the proteolytic profile of LF was unaltered by the pre-association of LF and OPN. Gastric proteolysis of LF was increased when the model gastric pH was reduced from 5.3 to 4.0, but less so when complexed with OPN. In a model of intestinal inflammation, undigested (79% inhibition) and gastric digestates (26% inhibition) of LF, but not gastrointestinal digestates, inhibited lipopolysaccharide (LPS)-induced NF-κB activation in intestinal epithelial cells. LF-OPN complexation sustained the inhibitory effect (21-43% of the undigested effect, depending on the type of complex) of LF after gastrointestinal digestion, suggesting that the peptides produced were different. In a neonatal rodent model used to study bone development, coacervating LF and OPN improved bone structures with a significant increase of trabecular proportion (BV/TV increase by 21.7%). This resulted in an 11.3% increase in stiffness of bones. Feeding the LF and OPN proteins in coacervate format also increased the levels of OPN, P1NP and M-CSF in blood, signifying a more pronounced impact on bone development. This research demonstrated that LF-OPN complexation and complex coacervation can delay simulated infant gastrointestinal digestion of LF and protect or improve the bioactivity of the proteins.

An expert panel on the adequacy of safety data and physiological roles of dietary bovine osteopontin in infancy

Human milk, due to its unique composition, is the optimal standard for infant nutrition. Osteopontin (OPN) is abundant in human milk but not bovine milk. The addition of bovine milk osteopontin (bmOPN) to formula may replicate OPN's concentration and function in human milk. To address safety concerns, we convened an expert panel to assess the adequacy of safety data and physiological roles of dietary bmOPN in infancy. The exposure of breastfed infants to human milk OPN (hmOPN) has been well-characterized and decreases markedly over the first 6 months of lactation. Dietary bmOPN is resistant to gastric and intestinal digestion, absorbed and cleared from circulation within 8-24 h, and represents a small portion (<5%) of total plasma OPN. Label studies on hmOPN suggest that after 3 h, intact or digested OPN is absorbed into carcass (62%), small intestine (23%), stomach (5%), and small intestinal perfusate (4%), with <2% each found in the cecum, liver, brain, heart, and spleen. Although the results are heterogenous with respect to bmOPN's physiologic impact, no adverse impacts have been reported across growth, gastrointestinal, immune, or brain-related outcomes. Recombinant bovine and human forms demonstrate similar absorption in plasma as bmOPN, as well as effects on cognition and immunity. The panel recommended prioritization of trials measuring a comprehensive set of clinically relevant outcomes on immunity and cognition to confirm the safety of bmOPN over that of further research on its absorption, distribution, metabolism, and excretion. This review offers expert consensus on the adequacy of data available to assess the safety of bmOPN for use in infant formula, aiding evidence-based decisions on the formulation of infant formula.

Comparison of Non-Covalent and Covalent Interactions between Lactoferrin and Chlorogenic Acid

Adding polyphenols to improve the absorption of functional proteins has become a hot topic. Chlorogenic acid is a natural plant polyphenol with anti-inflammatory, antioxidant, and anticancer properties. Bovine lactoferrin is known for its immunomodulatory, anticancer, antibacterial, and iron-chelating properties. Therefore, the non-covalent binding of chlorogenic acid (CA) and bovine lactoferrin (BLF) with different concentrations under neutral conditions was studied. CA was grafted onto lactoferrin molecules by laccase catalysis, free radical grafting, and alkali treatment. The formation mechanism of non-covalent and covalent complexes of CA-BLF was analyzed by experimental test and theoretical prediction. Compared with the control BLF, the secondary structure of BLF in the non-covalent complex was rearranged and unfolded to provide more active sites, the tertiary structure of the covalent conjugate was changed, and the amino group of the protein participated in the covalent reaction. After adding CA, the covalent conjugates have better functional activity. These lactoferrin-polyphenol couplings can carry various bioactive compounds to create milk-based delivery systems for encapsulation.

A Gently Processed Skim Milk-Derived Whey Protein Concentrate for Infant Formula: Effects on Gut Development and Immunity in Preterm Pigs

SCOPE

Processing of whey protein concentrate (WPC) for infant formulas may induce protein modifications with severe consequences for preterm newborn development. The study investigates how conventional WPC and a gently processed skim milk-derived WPC (SPC) affect gut and immune development after birth.

METHODS AND RESULTS

Newborn, preterm pigs used as a model of preterm infants were fed formula containing WPC, SPC, extra heat-treated SPC (HT-SPC), or stored HT-SPC (HTS-SPC) for 5 days. SPC contained no protein aggregates and more native lactoferrin, and despite higher Maillard reaction product (MRP) formation, the clinical response and most gut and immune parameters are similar to WPC pigs. SPC feeding negatively impacts intestinal MRP accumulation, mucosa, and bacterial diversity. In contrast, circulating T-cells are decreased and oxidative stress- and inflammation-related genes are upregulated in WPC pigs. Protein aggregation and MRP formation increase in HTS-SPC, leading to reduced antibacterial activity, lactase/maltase ratio, circulating neutrophils, and cytotoxic T-cells besides increased gut MRP accumulation and expression of TNFAIP3.

CONCLUSION

The gently processed SPC has more native protein, but higher MRP levels than WPC, resulting in similar tolerability but subclinical adverse gut effects in preterm pigs. Additional heat treatment and storage further induce MRP formation, gut inflammation, and intestinal mucosal damage.

Effects of pasteurization on osteopontin concentrations in human breastmilk

BACKGROUND

Osteopontin (OPN) is an important breastmilk protein involved in infant intestinal, immunological, and brain development. However, little is known about how common milk pasteurization and storage techniques affect this important bioactive protein.

METHODS

Human milk osteopontin concentration was measured in single-donor fresh (n = 1) or frozen (n = 20) breastmilk, pooled Holder-pasteurized donor breastmilk (n = 11), and a shelf-stable (retort pasteurized) breastmilk product (n = 2) by ELISA. Single-donor breastmilk samples were subjected to pasteurization and/or freezing before measuring osteopontin concentrations.

RESULTS

Holder pasteurization of breastmilk resulted in an ∼50% decrease in osteopontin concentration within single-donor samples. Breastmilk from mothers of preterm infants trended toward higher osteopontin concentration than mothers of term infants; however, samples from preterm mothers experienced greater osteopontin degradation upon pasteurization. A commercial breastmilk product that underwent retort pasteurization had lower osteopontin concentration than a Holder-pasteurized pooled breastmilk product. Finally, freezing breastmilk prior to Holder pasteurization resulted in less osteopontin degradation than Holder pasteurization prior to freezing.

CONCLUSIONS

Commonly used breastmilk pasteurization and storage techniques, including freezing and Holder pasteurization, decrease the concentration of the bioactive protein osteopontin in human breastmilk. Holder pasteurization reduced osteopontin concentration by an average of 63%, while freezing resulted in an 8-12% decrease.

IMPACT

Pasteurization of human breastmilk significantly decreases the concentration of the bioactive protein osteopontin. Use of both pasteurization and freezing techniques for breastmilk preservation results in greater loss of osteopontin. This study presents for the first time an analysis of osteopontin concentrations in single-donor pasteurized milk samples.

Immunoregulation of bovine lactoferrin together with osteopontin promotes immune system development and maturation

The immune system of infants is partly weak and immature, and supplementation of infant formula can be of vital importance to boost the development of the immune system. Lactoferrin (LF) and osteopontin (OPN) are essential proteins in human milk with immunoregulation function. An increasing number of studies indicate that proteins have interactions with each other in milk, and our previous study found that a ratio of LF : OPN at 1 : 5 (w/w, denoted as LOP) had a synergistic effect on intestinal barrier protection. It remains unknown whether LOP can also exert a stronger effect on immunoregulation. Hence, we used an in vitro model of LPS-induced macrophage inflammation and in vivo models of LPS-induced intestinal inflammation and early life development. We showed that LOP increased the secretion of the granulocyte-macrophage colony-stimulating factor (132%), stem cell factor (167%) and interleukin-3 (176%) in bone marrow cells, as well as thymosin (155%) and interleukin-10 (161%) in the thymus, more than LF or OPN alone during development, and inhibited changes in immune cells and cytokines during the LPS challenge. In addition, analysis of the components of digested proteins in vitro revealed that differentially expressed peptides may provide immunoregulation. Lastly, LOP increased the abundance of Rikenellaceae, Muribaculum, Faecalibaculum, and Elisenbergiella in the cecum content. These results imply that LOP is a potential immunomodifier for infants and offers a new theoretical basis for infant formula innovation.

Bovine milk osteopontin improved intestinal health of pregnant rats fed a high-fat diet through improving bile acid metabolism

The main purpose of the current study was to investigate the ameliorative effects of bovine milk osteopontin (bmOPN) on the gut dysfunction of pregnant rats fed a high-fat diet (HFD). Bovine milk osteopontin was supplemented at a dose of 6 mg/kg body weight. Bovine milk osteopontin supplementation during pregnancy reduced colonic inflammation of HFD dams, and it also increased the colonic expression of ZO-1 and claudin-4 of HFD dams. Bovine milk osteopontin significantly enriched the relative abundance of Bacteroidetes, whereas it decreased Proteobacteria, Helicobacteraceae, and Desulfovibrionaceae in feces of HFD dams. The levels of isobutyric acid and pentanoic acid in the HFD + bmOPN group were higher than that of the HFD group. Functional predication analysis of microbial genomes revealed that bmOPN supplementation to HFD pregnancies changed 4 Kyoto Encyclopedia of Genes and Genomes pathways including bile acid biosynthesis. Further, bmOPN enriched hepatic taurochenodeoxycholic acid and tauroursodeoxycholic acid plus taurohyodeoxycholic acid in the gut of HFD maternal rats. Our findings suggested that bmOPN improved the gut health of HFD pregnant rats partially through modulating bile acid biosynthesis.

Synergistic effect of lactoferrin and osteopontin on intestinal barrier injury

Several studies indicate that the disruption of the intestinal epithelial barrier can lead to inflammatory bowel disease (IBD). Recent evidence has increasingly demonstrated that lactoferrin (LF) and osteopontin (OPN) can alleviate intestinal barrier injury. However, the potential synergistic effects of these two proteins and the mechanisms underlying their effects remain unclear. To address this question, we developed a lipopolysaccharide-induced intestinal barrier injury model in C57BL/6 N mice. Our findings demonstrated that the combination of LF and OPN at a 1:5 ratio exerts the strongest protective effect on the intestinal barrier, and it is more effective than LF or OPN alone. This protection is evidenced by the decrease in serum diamine oxidase (DAO) activity (1.66-fold decrease) and D-lactic content (1.51-fold decrease) and the reduced rate of FITC-labeled glucan transport across the jejunum (3.18-fold decrease). Moreover, the protein combination significantly promoted villi length (1.66-fold increase) and crypt depth (1.57-fold increase), improved tight junction protein structure and expression, and boosted the number of absorptive cells (4.34-fold increase) in the intestinal epithelium. Furthermore, the combination promoted crypt cell proliferation and differentiation via Notch signaling. In summary, our findings provide scientific evidence supporting the use of dietary intervention strategies for preventing IBD.

Milk Osteopontin and Human Health

Osteopontin (OPN) is a multifunctional protein found in all vertebrates. OPN is expressed in many different cell types, and is consequently found in most tissues and physiological secretions. OPN is involved in a multitude of biological processes, such as activation and regulation of the immune system; biomineralization; tissue-transformative processes, including growth and development of the gut and brain; interaction with bacteria; and many more. OPN is found in the highest concentrations in milk, where it is believed to initiate and regulate developmental, immunological and physiological processes in infants who consume milk. Processes for the isolation of bovine OPN for use in infant formula have been developed, and in recent years, many studies have investigated the effects of the intake of milk OPN. The purpose of this article is to review and compare existing knowledge about the structure and function of milk OPN, with a particular focus on the effects of milk OPN on human health and disease.

The Role of Lactoferrin in Intestinal Health

The intestine represents one of the first barriers where microorganisms and environmental antigens come into tight contact with the host immune system. A healthy intestine is essential for the well-being of humans and animals. The period after birth is a very important phase of development, as the infant moves from a protected environment in the uterus to one with many of unknown antigens and pathogens. In that period, mother's milk plays an important role, as it contains an abundance of biologically active components. Among these components, the iron-binding glycoprotein, lactoferrin (LF), has demonstrated a variety of important benefits in infants and adults, including the promotion of intestinal health. This review article aims to provide a compilation of all the information related to LF and intestinal health, in infants and adults.

Evidence for human milk as a biological system and recommendations for study design-a report from "Breastmilk Ecology: Genesis of Infant Nutrition (BEGIN)" Working Group 4

Human milk contains all of the essential nutrients required by the infant within a complex matrix that enhances the bioavailability of many of those nutrients. In addition, human milk is a source of bioactive components, living cells and microbes that facilitate the transition to life outside the womb. Our ability to fully appreciate the importance of this matrix relies on the recognition of short- and long-term health benefits and, as highlighted in previous sections of this supplement, its ecology (i.e., interactions among the lactating parent and breastfed infant as well as within the context of the human milk matrix itself). Designing and interpreting studies to address this complexity depends on the availability of new tools and technologies that account for such complexity. Past efforts have often compared human milk to infant formula, which has provided some insight into the bioactivity of human milk, as a whole, or of individual milk components supplemented with formula. However, this experimental approach cannot capture the contributions of the individual components to the human milk ecology, the interaction between these components within the human milk matrix, or the significance of the matrix itself to enhance human milk bioactivity on outcomes of interest. This paper presents approaches to explore human milk as a biological system and the functional implications of that system and its components. Specifically, we discuss study design and data collection considerations and how emerging analytical technologies, bioinformatics, and systems biology approaches could be applied to advance our understanding of this critical aspect of human biology.

Naturally Occurring N-Terminal Fragments of Bovine Milk Osteopontin Are Transported across Models of the Intestinal Barrier

Osteopontin (OPN) is a bioactive integrin-binding protein found in high concentrations in milk, where it is present both as a full-length protein and as several N-terminally derived fragments. OPN resists gastric digestion, and via interaction with receptors in the gut or by crossing the intestinal barrier into circulation, ingested milk OPN may influence physiological processes. The aim of this study was to investigate OPN interaction with intestinal cells and its transport across models of the intestinal barrier. Immunodetection of OPN incubated with Caco-2 cells at 4 °C and 37 °C showed that OPN binds to the intestinal cells, but it is not internalised. Transepithelial transport was studied using mono- and co-cultures of Caco-2 cells and mucus-producing HT29-MTX cells in transwell membranes. OPN was shown to cross the barrier models in a time-, temperature-, and energy-dependent process inhibited by wortmannin, indicating that the transport takes place via the transcytosis pathway. Analyses of the naturally occurring milk mixture of full-length and N-terminal fragments showed that the N-terminal fragments of OPN bound intestinal cells most effectively and that the fragments were transported across the intestinal membrane models. This suggests that proteolytic processing of OPN increases its biological activity after ingestion.

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.

The Effect of Human and Bovine Milk Osteopontin on Intestinal Caco-2 Cells: A Transcriptome Comparison

Osteopontin (OPN) is a multifunctional protein abundantly present in human milk, whereas the concentration is significantly lower in bovine milk. Human and bovine milk OPN are structurally similar and both proteins resist gastric digestion and reach the intestines in a bioactive form. Intervention studies have indicated the beneficial effects of supplementing infant formula with bovine milk OPN and several in vivo and in vitro studies have shown that bovine milk OPN positively influences intestinal development. To investigate the functional relationship, we compared the effect of simulated gastrointestinal digested human and bovine milk OPN on gene expression in Caco-2 cells. After incubation, total RNA was extracted and sequenced and transcripts were mapped to the human genome. Human and bovine milk OPN regulated the expression of 239 and 322 genes, respectively. A total of 131 genes were similarly regulated by the OPNs. As a control, a whey protein fraction with a high content of alpha-lactalbumin had a very limited transcriptional impact on the cells. Enrichment data analysis showed that biological processes related to the ubiquitin system, DNA binding, and genes associated with transcription and transcription control pathways were affected by the OPNs. Collectively, this study shows that human and bovine milk OPN have a significant and highly comparable effect on the intestinal transcriptome.

Reduction of multiple reaction monitoring protein target list using correlation analysis

High mass resolution mass spectrometry provides hundreds to thousands of protein identifications per sample, and quantification is typically performed using label-free quantification. However, the gold standard of quantitative proteomics is multiple reaction monitoring (MRM) using triple quadrupole mass spectrometers and stable isotope reference peptides. This raises the question how to reduce a large data set to a small one without losing essential information. Here we present the reduction of such a data set using correlation analysis of bovine dairy ingredients and derived products. We were able to explain the variance in the proteomics data set using only 9 proteins across all major dairy protein classes: caseins, whey, and milk fat globule membrane proteins. We term this method Trinity-MRM. The reproducibility of the protein extraction and Trinity-MRM methods was shown to be below 5% in independent experiments (multi-day single-user and single-day multi-user) using double cream. Further application of this reductionist approach might include screening of large sample cohorts for biologically interesting samples before analysis by high-resolution mass spectrometry or other omics methodologies.

Synthesis and Optimization of Deesterified Acacia-Alginate Nanohydrogel for Amethopterin Delivery

Naturally obtained materials are preferable for the production of biomedicine in biomedical applications. Acacia gum is has recently become a hopeful one in the biomedicine production due to its excellent properties, namely, emulsifier, stabilizing mediator, suspending agent, etc. In this novel work, we synthesised and characterized the deesterified Acacia gum-alginate nanohydrogel (DEA-AG NPs) as a carrier for amethopterin (ATN) delivery. This combination is used in the drug effectiveness and tissue engineering. In this work, the Taguchi route is implemented for estimating of particle size and zeta potential (mV) through optimization. Following three parameters are considered for this work: DEA solution concentration (0.008, 0.016, 0.024, and 0.032 w/v %), alginate molecular weight (3, 6, 9, and 12 MW), and ATN/DEA ratio (1 : 4, 1 : 8, 1 : 12, and 1 : 16 w/w %). In particle size analysis and zeta potential analysis, the DEA solution concentration is highly influenced. Minimum particle size is found as 148.50 nm. Similarly, maximum zeta potential is identified as 29.5 mV.

Milk Osteopontin for Gut, Immunity and Brain Development in Preterm Pigs

Deficient levels of milk osteopontin (OPN) in infant formula may partly account for developmental differences between infants fed formula or maternal milk. We hypothesized that a milk diet supplemented with bovine milk OPN improves gut, immunity and brain development and tested this in a preterm pig model. Preterm pigs delivered by cesarean section (90% gestation) were fed raw bovine milk (CON, n = 19) or the same diet supplemented with a physiologically relevant dose of OPN (46 mg/(kg·d), n = 16). Endpoints related to clinical outcomes, systemic immunity and neurocognitive development were assessed during the study and gut tissues were collected at Day 19. Growth pattern, early motor development and most systemic immune parameters were similar between OPN and CON pigs. The OPN pigs had higher villus-to-crypt ratios than CON pigs and higher monocyte and lymphocyte counts on Day 8. Gut digestive and absorptive functions and cognitive performance (T-maze test) were similar between OPN and CON pigs. In conclusion, dietary supplementation with OPN above basal bovine milk levels induced minor improvements in gut structure and systemic immunity without any effects on cognitive performance. The minimal levels of OPN in infant formula to secure optimal adaptation in the immediate neonatal period remain to be determined.

A literature review on lactopontin and its roles in early life

OBJECTIVE

Our study aims to review the functions and possible mechanisms of lactopontin (LPN) in early life.

BACKGROUND

Human milk proteins provide a variety of protection and health benefits in early life. One of these multifunctional proteins is LPN, which is osteopontin (OPN) derived from milk.

METHODS

Information used to write this paper was collected from Uniprot, PubMed, and Google Scholar, including in vitro, in vivo, and clinical studies.

CONCLUSIONS

LPN is a highly phosphorylated, O-glycosylated acidic protein and a unique type of OPN, as it presents at the highest concentration and a higher degree of posttranslational modifications (PTMs) in human milk than other tissues and excretions. LPN is present in milk and the intestinal tracts of infants after consumption as a mixture of intact protein and peptides, which can bind diverse integrin and receptors in the target cell and drive downstream signaling pathways. LPN is found to play important roles in developing the immune, intestinal and nervous systems in early life. Moreover, LPN has also shown to support preterm infants' health when they are especially vulnerable after delivery via animal studies. Additionally, LPN can form protein complex with another milk bioactive protein, lactoferrin (LF), to withstand proteolysis and perform more efficient biological activity. Therefore, LPN showed great potential for early life while more clinical trials and evidence are still emergying.

Recombinant Bovine and Human Osteopontin Generated by Chlamydomonas reinhardtii Exhibit Bioactivities Similar to Bovine Milk Osteopontin When Assessed in Mouse Pups Fed Osteopontin-Deficient Milk

SCOPE

Osteopontin (OPN), a highly phosphorylated and glycosylated protein, is present in most body fluids, including milk. OPN appears at a high concentration in human milk (130-180 mg L^-1 ), but not bovine milk (≈18 mg mL^-1 ). It is previously shown that milk OPN is involved in various biological processes and therefore may be a valuable infant formula additive.

METHODS AND RESULTS

In the present study, recombinant bovine OPN (rbOPN) and recombinant human OPN (rhOPN) are generated in a Chlamydomonas reinhardtii (C. reinhardtii) algal expression system. The rbOPN and rhOPN are phosphorylated but not glycosylated. To assess the bioactivities of rbOPN and rhOPN and compare their bioactivities to those of bovine milk OPN (bmOPN), wild-type (WT) mouse pups nursed by OPN knock-out (KO) dams are orally fed bmOPN, rbOPN, and rhOPN daily from postnatal days 1-21 (P1-21). Effects of these OPNs on development of the brain, intestine, and immune function are evaluated. The results show that rbOPN and rhOPN exhibit effects similar to those of bmOPN as well as mouse milk OPN on stimulating proliferation of the small intestine, increasing brain myelination and cognitive development, and enhancing development of immune function.

CONCLUSION

rbOPN and rhOPN are likely to provide beneficial bioactivities when added to infant diets.

Precision Nutrition in Chronic Inflammation

The molecular foundation of chronic inflammatory diseases (CIDs) can differ markedly between individuals. As our understanding of the biochemical mechanisms underlying individual disease manifestations and progressions expands, new strategies to adjust treatments to the patient's characteristics will continue to profoundly transform clinical practice. Nutrition has long been recognized as an important determinant of inflammatory disease phenotypes and treatment response. Yet empirical work demonstrating the therapeutic effectiveness of patient-tailored nutrition remains scarce. This is mainly due to the challenges presented by long-term effects of nutrition, variations in inter-individual gastrointestinal microbiota, the multiplicity of human metabolic pathways potentially affected by food ingredients, nutrition behavior, and the complexity of food composition. Historically, these challenges have been addressed in both human studies and experimental model laboratory studies primarily by using individual nutrition data collection in tandem with large-scale biomolecular data acquisition (e.g. genomics, metabolomics, etc.). This review highlights recent findings in the field of precision nutrition and their potential implications for the development of personalized treatment strategies for CIDs. It emphasizes the importance of computational approaches to integrate nutritional information into multi-omics data analysis and to predict which molecular mechanisms may explain how nutrients intersect with disease pathways. We conclude that recent findings point towards the unexhausted potential of nutrition as part of personalized medicine in chronic inflammation.

Label-free quantitative proteomics analysis reveals the fate of colostrum proteins in the intestine of neonatal calves

The contribution of intestinally absorbed colostral immunoglobulins to the transmission of passive immunity is widely reported in neonatal calves. However, changes in the colostral proteome in the gastrointestinal digesta remain unclear. Therefore, this study aimed to investigate changes in colostral proteome affected by gastrointestinal proteases in neonatal calves. Twenty-one neonatal Holstein calves were used in this study, including 18 colostrum-fed calves slaughtered at 8 (CI, n = 6), 24 (CII, n = 6), and 36 h (CIII, n = 6) postpartum and 3 milk-fed calves slaughtered 24 h postpartum (MI, n = 3). The ingested colostrum and milk samples were collected from the mid-jejunum segment, following the sacrifice. The undigested colostrum or milk along with their ingested colostrum or milk samples were investigated using a label-free proteomics approach. Hierarchical clustering and principal component analysis of the quantified proteins revealed that the ingested colostrum from the CII and CIII groups and the ingested mature milk from the MI group appeared to share similar patterns. Analysis of the intestinal digesta revealed a time-dependent decrease in caseins, lactoferrin, and osteopontin protein levels, and an increase in cationic trypsin, chymotrypsin, and carboxypeptidase. Several protease inhibitors, such as α-1-antiproteinase, α-2-antiplasmin, and early lactation protein, were identified in the colostrum and intestinal digesta. In addition, we detected identical levels in the intestinal digesta and colostrum for albumin, α-1-acid glycoprotein, and plasminogen. Pathway analysis indicated that proteins increased in the intestinal digesta belonged to the following categories: biosynthesis of antibiotics, carbon metabolism, and biosynthesis of amino acids. These results indicated that selected colostral proteins were digested by gastrointestinal proteases, contributing to their intestinal absorption in calves. These findings provide new insights into the fate of the colostral proteome in the gastrointestinal tract and may aid in the identification of factors contributing to health management in neonatal calves.

Biological activities of commercial bovine lactoferrin sources

Lactoferrin (Lf) samples from several manufacturers were evaluated in vitro. The purity and protein form of each Lf were examined by SDS-PAGE, Western blot, and proteomics analysis. Assays were conducted to evaluate uptake of Lfs and iron from Lfs by enterocytes as well as Lf bioactivities, including effects on intestinal cell proliferation and differentiation, IL-18 secretion, TGF-β1 transcription, and growth of enteropathogenic Escherichia coli (EPEC). Composition of the Lfs varies; some only contain a major Lf band (∼80 kDa), and some also contain minor forms. All Lfs and iron from the Lfs were absorbed by Caco-2 cells, with various efficiencies. The bioactivities of the Lfs varied considerably, but there was no consistent trend. All Lfs promoted intestinal cell proliferation, secretion of IL-18, and transcription of TGF-β1. Some Lfs exhibited pro-differentiation effects on Caco-2 cells. Effects of pasteurization (62.5 °C for 30 min, 72 °C for 15 s, or 121 °C for 5 min) on integrity, uptake, and bioactivities were examined using Dicofarm, Tatua, and native bovine Lfs. Results show that pasteurization did not affect protein integrity, but variously affected uptake of Lf and its effects on intestinal proliferation, differentiation, and EPEC growth. To choose a Lf source for a clinical trial, assessment of bioactivities is recommended.

Evaluation of Bioactivities of the Bovine Milk Lactoferrin-Osteopontin Complex in Infant Formulas

Human milk contains several bioactive proteins, including lactoferrin (LF) and osteopontin (OPN). These two proteins have been shown to form a complex, which shows increased bioactivities. Bovine LF and OPN can also form such a complex. We assessed bioactivities of the bovine LF-OPN complex (at molar ratios of LF:OPN = 3:1, 5:1, or 8:1) in a formula protein matrix, including LF, OPN, bovine whey protein hydrolysate, and α-lactalbumin. Our results show that the bovine LF-OPN complex together with formula proteins is resistant to in vitro digestion, stimulates intestinal cell proliferation (by 15-50%) and differentiation (by 30-50%), increases antibacterial activity (by 25-50%), and enhances intestinal immunity. The 3:1 ratio of LF to OPN exhibits the most potent effects, as compared with the other two ratios. In conclusion, adding bovine LF and OPN to infant formulas may result in increased stability of the two components and enhanced bioactivities, possibly improving outcomes in formula-fed infants.

Bioactive peptides derived from human milk proteins: an update

PURPOSE OF REVIEW

Human milk contains a variety of bioactive proteins, and some of the bioactivities are exerted only after proteins are digested in the gastrointestinal tract. This review aims to overview recent studies on bioactive peptides in human milk and gastric digesta of breast-fed infants.

RECENT FINDINGS

Milk protein-derived peptides are endogenously present in human milk, and some of them have been reported to be bioactive peptides, such as a homologue of caseinophosphopeptide, an antimicrobial peptide, and an immunomodulatory peptide. A larger number of peptides are identified in gastric aspirates from breast-fed infants, and bioactive peptides such as angiotensin I-converting enzyme-inhibitory peptides, an antioxidative peptide, opioid agonist peptides are only found in the digesta of human milk but not in human milk per se. Casein is the greatest source of released bioactive peptides.

SUMMARY

Technological advances have considerably increased our capability to identify and characterize peptides derived from human milk proteins. However, their physiological significance and the roles of these bioactive peptides in growth and development of breast-fed infants have not yet been sufficiently elucidated, and further in-vivo experiments and clinical trials are warranted.