An intact gut microbiota may be required for lactoferrin-driven immunomodulation in rats

Unlocking the power of Lactoferrin: Exploring its role in early life and its preventive potential for adult chronic diseases

Nutrition during the early postnatal period exerts a profound impact on both infant development and later-life health. Breast milk, which contains lactoferrin, a dynamic protein, plays a crucial role in the growth of various biological systems and in preventing numerous chronic diseases. Based on the relationship between early infant development and chronic diseases later in life, this paper presents a review of the effects of lactoferrin in early life on neonates intestinal tract, immune system, nervous system, adipocyte development, and early intestinal microflora establishment, as well as the preventive and potential mechanisms of early postnatal lactoferrin against adult allergy, inflammatory bowel disease, depression, cancer, and obesity. Furthermore, we summarized the application status of lactoferrin in the early postnatal period and suggested directions for future research.

Schizochytrium sp. and lactoferrin supplementation alleviates Escherichia coli K99-induced diarrhea in preweaning dairy calves

Calf diarrhea, a common disease mainly induced by Escherichia coli infection, is one of the main reasons for nonpredator losses. Hence, an effective nonantibacterial approach to prevent calf diarrhea has become an emerging requirement. This study evaluated the microalgae Schizochytrium sp. (SZ) and lactoferrin (LF) as a nutrient intervention approach against E. coli O101:K99-induced preweaning calve diarrhea. Fifty 1-d-old male Holstein calves were randomly divided into 5 groups (n = 10): (1) control, (2) blank (no supplement or challenge), (3) 1 g/d LF, (4) 20 g/d SZ, or (5) 1 g/d LF plus 20 g/d SZ (LFSZ). The experimental period lasted 14 d. On the morning of d 7, calves were challenged with 1 × 1011 cfu of E. coli O101:K99, and rectum feces were collected on 3, 12, 24, and 168 h postchallenge for the control, LF, SZ, and LFSZ groups. The rectal feces of the blank group were collected on d 14. Data were analyzed using the mixed procedure of SAS (version 9.4; SAS Institute Inc.). The E. coli K99 challenge decreased the average daily gain (ADG) and increased feed-to-gain ratio (F:G) and diarrhea frequency (control vs. blank). Compared with the control group, the LFSZ group had a higher ADG and lower F:G, and the LFSZ and SZ groups had lower diarrhea frequency compared with the control group. In addition, the LFSZ and SZ groups have no differences in diarrhea frequency compared with the blank group. Compared with the control group, the blank group had lower serum nitric oxide (NO), endothelin-1, d-lactic acid (D-LA), and lipopolysaccharide (LPS) concentrations, as well as serum IgG, IL-1β, IL-6, IL-10, and TNF-α levels on d 7 and 14. On d 7, compared with the control group, all treatment groups had lower serum NO level, the SZ group had a lower serum D-LA concentration, and the LF and LFSZ groups had lower serum LPS concentration. On d 14, compared with the control group, the fecal microbiota of the blank group had lower Shannon, Simpson, Chao1, and ACE indexes, the LFSZ group had lower Shannon and Simpson indexes, the SZ and LFSZ groups had a higher Chao1 index, and all treatment groups had a higher ACE index. In fecal microbiota, Bifidobacterium and Actinobacteria were negatively associated with IL-10 and d-lactate, while Akkermansia was negatively associated with endothelin-1 and positively correlated with LPS, fecal scores, and d-lactate levels. Our results indicated that LF and SZ supplements could alleviate E. coli O101:K99-induced calf diarrhea individually or in combination. Supplementing 1 g/d LF and 20 g/d SZ could be a potential nutrient intervention approach to prevent bacterial diarrhea in calves.

Proteolysis of vaginally administered bovine lactoferrin: clearance, inter-subject variability, and implications for clinical dosing

This report describes proteolytic fragmentation and clearance of bovine lactoferrin (bLF) upon intravaginal administration in premenopausal women. Tablet formulations (MTbLF) containing 300 mg of bLF progressed through three phases: Pre-Dissolution, Dissolution, and Washout, over a 30-h time course. Tablets dissolved slowly, replenishing intact 80 kDa bLF in vaginal fluid (VF) as proteolysis occurred. bLF was initially cleaved approximately in half between its N- and C-lobes, then degraded into sub-fragments and small peptides. The extent of proteolysis was less than 10-20% across multiple subjects. Concentrations of both intact 80 kDa bLF and smaller fragments decreased in VF with a similar time course suggesting washout not proteolysis was the main clearance mechanism. Concentrations of intact and/or nicked 80 kDa bLF peaked between 4 and 8 h after administration and remained above 5 mg/mL for approximately 24 h. Experiments with protease inhibitors in ex vivo VF digests suggested an aspartyl protease was at least partially responsible for bLF cleavage. However, digestion with commercial pepsin or in vivo in the human stomach, demonstrated distinctly different patterns of fragments compared to vaginal proteolysis. Furthermore, the 3.1 kDa antimicrobial peptide lactoferricin B was not detected in VF. This suggests pepsin-like aspartyl proteases are not responsible for vaginal proteolysis of bLF.

Research Advances of Lactoferrin in Electrostatic Spinning, Nano Self-Assembly, and Immune and Gut Microbiota Regulation

Lactoferrin (LF) is a naturally present iron-binding globulin with the structural properties of an N-lobe strongly positively charged terminus and a cage-like structure of nano self-assembly encapsulation. These unique structural properties give it potential for development in the fields of electrostatic spinning, targeted delivery systems, and the gut-brain axis. This review will provide an overview of LF's unique structure, encapsulation, and targeted transport capabilities, as well as its applications in immunity and gut microbiota regulation. First, the microstructure of LF is summarized and compared with its homologous ferritin, revealing both structural and functional similarities and differences between them. Second, the electrostatic interactions of LF and its application in electrostatic spinning are summarized. Its positive charge properties can be applied to functional environmental protection packaging materials and to improving drug stability and antiviral effects, while electrostatic spinning can promote bone regeneration and anti-inflammatory effects. Then the nano self-assembly behavior of LF is exploited as a cage-like protein to encapsulate bioactive substances to construct functional targeted delivery systems for applications such as contrast agents, antibacterial dressings, anti-cancer therapy, and gene delivery. In addition, some covalent and noncovalent interactions of LF in the Maillard reaction and protein interactions and other topics are briefly discussed. Finally, LF may affect immunological function via controlling the gut microbiota. In conclusion, this paper reviews the research advances of LF in electrostatic spinning, nano self-assembly, and immune and gut microbiota regulation, aiming to provide a reference for its application in the food and pharmaceutical fields.

Limosilactobacillus reuteri SLZX19-12 Protects the Colon from Infection by Enhancing Stability of the Gut Microbiota and Barrier Integrity and Reducing Inflammation

Limosilactobacillus reuteri plays an important role in regulating intestinal functions and maintaining barrier integrity in animals. In this study, Limosilactobacillus reuteri strain SLZX19-12 was isolated from the fecal microbiota of Tibetan pigs, and it was found that this strain is sensitive to common antibiotics and has strong resistance to stress. Upon being administered by gavage at different doses, including low, medium, and high doses, for 14 days, Limosilactobacillus reuteri SLZX19-12 may enhance the intestinal barrier. After administration of a high dose of SLZX19-12, mice were challenged with Salmonella enterica serovar Typhimurium SL1344. Infection with Salmonella Typhimurium SL1344 led to disordered colonic microbiotas, colonic inflammation through the S100A8/S100A9-NF-κB pathway and potential apoptosis, and translocation of pathogens to parenteral visceral organs in mice. However, the mice pretreated with Limosilactobacillus reuteri SLZX19-12 showed lower loads of Salmonella in visceral organs, less colonic inflammation, and higher barrier integrity. More importantly, the administration of strain SLZX19-12 resulted in a more stable microbiota structure of the colon, in which the abundance of Alloprevotella was greatly enhanced. Therefore, this study suggests that Limosilactobacillus reuteri SLZX19-12 can protect the colon from infection by enhancing the stability of gut microbiota and barrier integrity and reducing inflammation. IMPORTANCE The use of antibiotics to treat bacterial infections leads to a series of side effects. As an alternative method, the biocontrol strategy, which uses probiotics to suppress pathogens, is considered a potential way to deal with bacterial infections in gut. However, there are few probiotics that are currently safe and can protect against infection. In this study, Limosilactobacillus reuteri strain SLZX19-12 was obtained from Tibetan pigs, which have higher resistance to infection. This strain is sensitive to conventional antibiotics, secretes a wide spectrum of enzymes, and also promotes the intestinal barrier function in mice. In addition, Limosilactobacillus reuteri SLZX19-12 can promote the stability of the gut microbiota to avoid or alleviate the occurrence or development of foodborne infections.

Characterization of proteolytic degradation products of vaginally administered bovine lactoferrin

When bovine lactoferrin (bLF) contacts human vaginal fluid (VF) it is subjected to proteolytic degradation. This report describes fragmentation patterns of bLF dosed vaginally in clinical trials or incubated ex vivo with VF. A consensus pattern of fragments was observed in samples from different women. The 80 kDa bLF molecule is initially cleaved between its homologous 40 kDa domains, the N-lobe and C-lobe, and then degraded into sub-fragments and mixtures of small peptides. We characterized this fragmentation process by polyacrylamide gel electrophoresis, western blotting, chromatographic separation, and mass spectral sequence analysis. Common to most VF fragmentation patterns were large amounts of an N-lobe 37 kDa fragment and a C-lobe 43 kDa fragment resulting from a single cleavage following tyrosine 324. Both fragments possessed full sets of iron-ligand amino acids and retained iron-binding ability. In some VF samples, alternative forms of large fragments were found, which like the 37+43 kDa pair, totaled 80 kDa. These included 58+22 kDa, 18+62 kDa, and 16+64 kDa forms. In general, the smaller component was from the N-lobe and the larger from the C-lobe. The 18+62 kDa pair was absent in some VF samples but highly abundant in others. This variability suggests multiple endopeptidases are involved, with the 18 kDa fragment’s presence dependent upon the balance of enzymes. Further action of VF endopeptidases produced smaller peptide fragments, and we found evidence that exopeptidases trimmed their N- and C-termini. The 3.1 kDa antimicrobial peptide lactoferricin B was not detected. These studies were facilitated by a novel technique we developed: tricolor western blots, which enabled simultaneous visualization of N- and C-terminal epitopes.

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.

Pyroglutamyl leucine, a peptide in fermented foods, attenuates dysbiosis by increasing host antimicrobial peptide

PyroGlu-Leu is present in certain food protein hydrolysates and traditional Japanese fermented foods. Our previous study demonstrated that the oral administration of pyroGlu-Leu (0.1 mg/kg body weight) attenuates dysbiosis in mice with experimental colitis. The objective of this study was to elucidate why such a low dose of pyroGlu-Leu attenuates dysbiosis in different animal models. High fat diet extensively increased the ratio of Firmicutes/Bacteroidetes in feces of rats compared to control diet. Oral administration of pyroGlu-Leu (1 mg/kg body weight) significantly attenuated high fat diet-induced dysbiosis. By focusing on the production of intestinal antimicrobial peptides, we found that pyroGlu-Leu significantly increased the level of 4962 Da peptides, which identified as the propeptide of rattusin or defensin alpha 9, in ileum. We also observed increased tryptic fragment peptides from rattusin in the lumen. Here, we report that orally administered pyroGlu-Leu attenuates dysbiosis by increasing in the host antimicrobial peptide, rattusin.

Antilisterial activity of dromedary lactoferrin peptic hydrolysates

The aim of this study was to explore the antibacterial peptides derived from dromedary lactoferrin (LFc). The LFc was purified from colostrum using a batch procedure with a cation exchange chromatography support and was hydrolyzed with pepsin to generate peptic digest. This peptic digest was fractionated by cation exchange chromatography, and the antilisterial activity of LFc, peptic digest, and obtained fractions was investigated using the bioscreen method. The growth of Listeria innocua ATCC 33090 and LRGIA 01 strains was not inhibited by LFc and its hydrolysates. Two fractions of dromedary lactoferrin peptic hydrolysate were active against both strains. A tandem mass spectroscopy analysis revealed that the 2 active fractions comprised at least 227 different peptides. Among these peptides, 9 found in the first fraction had at least 50% similarity with 10 known antimicrobial peptides (following sequence alignments with the antimicrobial peptide database from the University of Nebraska Medical Center, Omaha). Whereas 9 of these peptides presented homology with honeybee, frog, or amphibian peptides, the 10th peptide, F₁₅₂SASCVPCVDGKEYPNLCQLCAGTGENKCACSSQEPYFGY₁₉₂ (specifically found in 1 separated fraction), exibited 54% homology with a synthetic antibacterial peptide (AP00481) derived from human lactoferrin named kaliocin-1. Similarly, the second fraction contained 1 peptide similar to lactoferrampin B, an antibacterial peptide derived from bovine milk. This result suggests that peptic hydrolysis of LFc releases more active antimicrobial peptides than their protein source and thus provides an opportunity for their potential use to improve food safety by inhibiting undesirable and spoilage bacteria.