Critical Importance of Iron Saturation in Lactoferrin: Effects on Biological Activity, Nutritional Functions, and Applications

Lactoferrin (LF), a multifunctional glycoprotein with high iron-binding affinity, plays a critical role in modulating physiological processes through its ability to reversibly bind and release iron ions, existing in two distinct states: iron-saturated (holo-LF, > 85% saturation) and iron-deficient (apo-LF, < 5% saturation). However, the importance of iron saturation has been largely overlooked in LF production and research due to the lack of standardized protocols. The iron saturation level of LF dictates its functional specificity: apo-LF exhibits potent antimicrobial properties by chelating iron and disrupting membrane integrity, while also significantly inhibiting oxidative stress, thereby alleviating neurological disorders and modulating immune responses. In contrast, holo-LF participates in iron metabolism and transport, influencing tumor cell proliferation and systemic iron uptake. This review systematically evaluates the interplay between iron saturation levels and LF's biological functions, emphasizing its dual roles in human iron homeostasis and disease modulation. Future research should prioritize elucidating the mechanisms underlying iron saturation-dependent bioactivity and metabolic differences, while incorporating emerging technologies to enhance LF stability and refine iron saturation measurement accuracy.

Lactoferrin modulates oxidative stress and inflammatory cytokines in a murine model of dysbiosis induced by clindamycin

Antibiotics, specifically clindamycin (Clin), cause intestinal dysbiosis, reducing the microbiota with anti-inflammatory properties. Furthermore, Clin can induce alterations in the immune responses and oxidative stress. Lactoferrin, among other activities, participates in the maintenance of intestinal homeostasis and reduces dysbiosis induced by antibiotic treatment. The aim of this study was to analyze the effect of native and iron-saturated bovine LF in a murine model of dysbiosis induced by Clin. Six groups of male C57BL/6 mice were treated with saline (control), Clin, native lactoferrin (nLF), iron-saturated lactoferrin (sLF), nLF/Clin, or sLF/Clin. Oxidation caused in the intestinal cells of the ileum of animals subjected to different treatments was analyzed, focusing on lipid peroxidation and protein carbonyl content. The expression of inflammatory mediators was determined by qRT-PCR. Treatment with Clin did not modify lipid peroxidation, but significantly increased protein carbonyl levels up to almost 5-fold respect to the control, an effect that was reversed by orally administering sLF to mice. Furthermore, Clin increased the expression of interleukin-6 and TNF-α by 1- and 2-fold change, respectively. This effect was reversed by treatment with nLF and sLF, decreasing the expression to basal levels. In conclusion, this study indicates that lactoferrin can prevent some of the effects of Clin on intestinal cells and their associated immune system.

Application of lipopolysaccharide in establishing inflammatory models

Lipopolysaccharide (LPS), a unique component of the outer membrane of Gram-negative bacteria, possesses immune-activating properties. It induces an immune response by stimulating host cells to produce a lot of inflammatory cytokines with a thermogenic effect, which may cause an inflammatory response. In the past few decades, the structure and function of LPS and its mechanism leading to inflammation have been extensively analyzed. Since LPS can cause inflammation, it is often used to establish inflammation models. These models are crucial in the study of inflammatory diseases that pose a serious threat to human health. In addition, the non-pro-inflammatory effects of LPS under certain circumstances are also being studied widely. This review summarizes the methods by which LPS has been used to establish inflammatory models at the cellular and animal levels to study related diseases. It also introduces in detail the evaluation indicators necessary for the successful establishment of these models, providing a reference for future research.

Evaluation of the protective bioactivity and molecular mechanism verification of lactoferrin in an Alzheimer's mouse model with ulcerative enteritis

The development of new drug therapies for Alzheimer's disease (AD) is an important research topic today, but the pathogenesis of AD has not been thoroughly studied, and there are still several shortcomings in existing drug therapies. Therefore, this study aimed to explore the molecular mechanism of lactoferrin (LF) in the treatments of AD and ulcerative colitis (UC) that is susceptible to AD, starting from the principle of one drug, two diseases, and the same treatment. This study used pathological staining and specific indicator staining to preliminarily evaluate the interventions of LF on UC injury and AD progression. We also used 16s RNA full-length sequencing to investigate the effect of LF on the abundance of intestinal microbiota in AD mice. Intestinal tissue and brain tissue metabolomics analysis were then used to screen specific metabolic pathways and preliminarily verify the metabolic mechanism of LF in alleviating the 2 diseases by regulating certain specific metabolites. Moreover, LF significantly changed the types and abundance of gut microbiota in AD mice complicated by UC. To conclude, this study proved the clinical phenomenon of AD susceptibility to UC, and verified the therapeutic effect of LF on 2 diseases. More importantly, we revealed the possible molecular mechanism of LF: Not only does it enrich the cognitive level of LF in alleviating AD by regulating the gut microbiota through the brain gut axis from the perspective of the theory of food nutrition promoting human health, but it also provides a practical basis for the subsequent research and development of LF and drug validation from the perspective of drug food homology.

The Iron Binding Ability Maps the Fate of Food-Derived Transferrins: A Review

As the demand for lactoferrin increases, the search for cost-effective alternative proteins becomes increasingly important. Attention naturally turns to other members of the transferrin family such as ovotransferrin. The iron-binding abilities of these proteins influence their characteristics, although the underlying mechanisms remain unclear. This overview systematically summarizes the effects of the iron-binding ability on the fate of food-derived transferrins (lactoferrin and ovotransferrin) and their potential applications. The findings indicate that iron-binding ability significantly influences the structure of food-derived transferrins, particularly their tertiary structure. Changes in structure influence their physicochemical properties, which, in turn, lead to different behaviors in response to environmental variations. Thus, these proteins exhibit distinct digestive characteristics by the time they reach the small intestine, ultimately performing varied physiological functions in vivo. Consequently, food-derived transferrins with different iron-binding states may find diverse applications. Understanding this capability is essential for developing food-derived transferrins and driving innovation in lactoferrin-related industries.

A review of the biological activities of lactoferrin: mechanisms and potential applications

Lactoferrin, a multifunctional iron-binding protein found in milk and other body fluids, possesses numerous biological activities. The functional activity of lactoferrin lies not only in its iron-binding capacity but also in the molecular mechanisms by which it can affect important chemical components in the host. However, the molecular mechanisms underlying these activities remain unelucidated. In this paper, we review the structure, properties, and contents of different lactoferrin milk sources. The different biological activities, namely antibacterial, antiviral, immunomodulatory, anti-inflammatory, bone regeneration, and improved metabolic disorder bioactivities, and the associated potential mechanisms of lactoferrin are summarized with the aim of providing a reference for the development of lactoferrin-related products.

Bovine lactoferrin inhibits inflammatory response and apoptosis in lipopolysaccharide-induced acute lung injury by targeting the PPAR-γ pathway

BACKGROUND

Lactoferrin (LF) is an iron-binding multifunctional cationic glycoprotein. Previous studies have demonstrated that LF may be a potential drug for treating acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). In this study, we explored the anti-inflammatory effect and mechanism of bovine lactoferrin (bLF) in ALI using the RNA sequencing (RNA-seq) technology and transcriptome analysis.

METHODS AND RESULTS

Based on the differentially expressed genes (DEGs) obtained from RNA-seq of the Lung from mouse model, the bioinformatics workflow was implemented using the BGISEQ-500 platform. The protein-protein interaction (PPI) network was obtained using STRING, and the hub gene was screened using Cytoscape. To verify the results of transcriptome analysis, the effects of bLF on Lipopolysaccharide (LPS)-induced BEAS-2B cells and its anti-reactive oxygen species (ROS), anti-inflammatory, and antiapoptotic effects were studied via Cell Counting Kit-8 (CCK-8) test, active oxygen detection test, ELISA, and western blot assay. Transcriptome analysis revealed that two hub gene modules of DEGs were screened via PPI analysis using the STRING and MCODE plug-ins of Cytoscape. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that these core modules are enriched in the PPAR (peroxisome proliferator-activated receptor) and AMPK (AMP-activated protein kinase) signaling pathways. Through cell experiments, our study shows that bLF can inhibit ROS, inflammatory reaction, and LPS-induced BEAS-2B cell apoptosis, which are significantly antagonized by the PPAR-γ inhibitor GW9662.

CONCLUSION

This study has suggested that the PPAR-γ pathway is the critical target of bLF in anti-inflammatory reactions and apoptosis of ALI, which provides a direction for further research.

The alleviative effects comparison of four flavonoids from bamboo leaves on ulcerative colitis in an Alzheimer mouse model

BACKGROUND

Clinically, patients with dementia are at high risk of developing enteritis, especially those with AD. This study explored the potential therapeutic benefits of bamboo leaf flavonoids (BLF) for ulcerative colitis (UC) treatment in Alzheimer's disease (AD) mouse model.

METHODS

Various methods were employed, including pathological staining of brain/colon tissue, inflammatory cytokine detection in serum, and oxidative stress indicator assessment to compare ulcerative enteritis (UC) injury in normal and AD mice and determine whether AD mice were susceptible to colitis. Then, the effects of BLF on UC and AD were investigated via several unique indices further to determine whether it alleviated colitis injury and possessed beneficial properties. Moreover, four main components of BLF were utilized to treat primary colon epithelial cells and neuron cells to compare their effects in alleviating inflammation and oxidation. Furthermore, homoorientin embedded with ursolic acid was detected by HPLC and the in vitro release simulation experiments of the nanoparticles were performed.

RESULTS

BLF complexes positively impacted ulcerative colitis by reducing disease activity, it also helped to reduce inflammation. Moreover, the BLF complexes decreased oxidative stress in the brain and colon tissues, indicating its potential as a neuroprotective agent. The flavonoid complexes reduced the expression levels of GFAP, Iba-1, and Aβ in the brain tissue, highlighting its role in attenuating neuroinflammation and AD pathology. Additionally, the embedded homoorientin coated with ursolic acid showed stronger bioactivities when compared with the uncoated group.

CONCLUSION

These results suggest that BLF complexes and its four main chemicals may be useful for treating AD- and UC-related complications, the embedded homoorientin coated with ursolic acid even demonstrated stronger bioavailability than homoorientin. Considering BLF complexes were verified to suppress the progressions of AD and UC for the first time, and the embedded homoorientin was never reported in published articles, the present study might provide a new perspective on its potential applications.

Nutraceutical and Health-Promoting Potential of Lactoferrin, an Iron-Binding Protein in Human and Animal: Current Knowledge

Lactoferrin is a natural cationic iron-binding glycoprotein of the transferrin family found in bovine milk and other exocrine secretions, including lacrimal fluid, saliva, and bile. Lactoferrin has been investigated for its numerous powerful influences, including anticancer, anti-inflammatory, anti-oxidant, anti-osteoporotic, antifungal, antibacterial, antiviral, immunomodulatory, hepatoprotective, and other beneficial health effects. Lactoferrin demonstrated several nutraceutical and pharmaceutical potentials and have a significant impact on improving the health of humans and animals. Lactoferrin plays a critical role in keeping the normal physiological homeostasis associated with the development of pathological disorders. The current review highlights the medicinal value, nutraceutical role, therapeutic application, and outstanding favorable health sides of lactoferrin, which would benefit from more exploration of this glycoprotein for the design of effective medicines, drugs, and pharmaceuticals for safeguarding different health issues in animals and humans.

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.

Antimicrobial Effects of Lactoferrin against Helicobacter pylori Infection

Helicobacter (H.) pylori is the primary causative agent of various gastroduodenal diseases. H. pylori is an adapted microorganism that has evolved to survive in the acidic conditions of the human stomach, possessing a natural strategy for colonizing harsh environments. Despite the implementation of various eradication regimens worldwide, the eradication rate of H. pylori has decreased to less than 80% in recent years due to the emergence of antibiotic-resistant strains. This has posed a significant challenge in treating H. pylori infection, as antibiotic resistance and side effects have become increasingly problematic. Lactoferrin, a member of the transferrin family, is an iron-binding protein with antioxidant, antibacterial, antiviral, and anti-inflammatory properties that promote human health. The concentrations of lactoferrin in the gastric juice and mucosa significantly increase during H. pylori infection and are strongly correlated with the severity of gastric mucosal inflammation. Numerous researchers have studied the antimicrobial properties of lactoferrin both in vitro and in vivo. In addition, recent studies have investigated the addition of oral lactoferrin supplementation to H. pylori eradication therapy, even though monotherapy with lactoferrin does not eradicate the microorganism. In this article, we reviewed the survival strategy of H. pylori to evade the antimicrobial activity of human lactoferrin and explore the potential of lactoferrin in H. pylori eradication therapy.

Preventive effect of Terminalia bellirica (Gaertn.) Roxb. extract on mice infected with Salmonella Typhimurium

Terminalia bellirica (Gaertn.) Roxb. (TB) is a traditional herbal combination used in Chinese medicine for the treatment of a broad range of diseases. In this study, thirty KM mice were randomly divided into control (N), infection group (NS), and the TB protection group (HS). Based on its digestive feature, intestinal physical barrier, immunological barrier and gut microbiota effects in vivo on challenged with S.typhimurium mice were investigated after oral administration of 600 mg/kg b.wt of TB for 13 days. The results show that the extract could improve the level of serum immunoglobulins (IgA and IgG), decrease the intestinal cytokine secretion to relieve intestinal cytokine storm, reinforce the intestinal biochemical barrier function by elevating the sIgA expression, and strengthen the intestinal physical barrier function. Simultaneously, based on the V3-V4 region of the 16S rRNA analyzed, the results of the taxonomic structure of the intestinal microbiota demonstrated that the TB prevention effect transformed the key phylotypes of the gut microbiota in S. Typhimurium-challenged mice and promoted the multiplication of beneficial bacteria. Furthermore, the abundance of Firmicutes and Deferribacteres increased, while that of Bacteroidetes and Actinobacteria decreased. At the genus level, the abundance of Ruminococcus and Oscillospira was substantially enhanced, while the other dominant genera showed no significant change between the vehicle control groups and the TB prevention groups. In summary, these results provide evidence that the administration of TB extract can prevent S. Typhimurium infection by alleviating the intestinal physical and immunological barriers and normalizing the gut microbiota, highlighting a promising application in clinical treatment. Thus, our results provide new insights into the biological functions of TB for the preventive effect of intestinal inflammation.

Lactoferrin: A glycoprotein that plays an active role in human health

Lactoferrin (Lf), existing widely in human and mammalian milk, is a multifunctional glycoprotein with many functions, such as immune regulation, anti-inflammation, antibacterial, antiviral, and antioxidant. These extensive functions largely attribute to its ability to chelate iron and interfere with the cellular receptors of pathogenic microorganisms and their hosts. Moreover, it is non-toxic and has good compatibility with other supplements. Thus, Lf has been widely used in food nutrition, drug carriers, biotechnology, and feed development. Although Lf has been continuously explored and studied, a more comprehensive and systematic compendium is still required. This review presents the recent advances in the structure and physicochemical properties of Lf as well as clinical studies on human diseases, with the aim of providing a reference for further research of Lf and the development of its related functional products.

Lactoferrin Alleviates Lipopolysaccharide-Induced Infantile Intestinal Immune Barrier Damage by Regulating an ELAVL1-Related Signaling Pathway

As the most important intestinal mucosal barrier of the main body, the innate immune barrier in intestinal tract plays especially pivotal roles in the overall health conditions of infants and young children; therefore, how to strengthen the innate immune barrier is pivotal. A variety of bioactivities of lactoferrin (LF) has been widely proved, including alleviating enteritis and inhibiting colon cancer; however, the effects of LF on intestinal immune barrier in infants and young children are still unclear, and the specific mechanism on how LF inhibits infantile enteritis by regulating immune signaling pathways is unrevealed. In the present study, we firstly performed pharmacokinetic analyses of LF in mice intestinal tissues, stomach tissues and blood, through different administration methods, to confirm the metabolic method of LF in mammals. Then we constructed in Vitro and in Vivo infantile intestinal immune barrier damage models utilizing lipopolysaccharide (LPS), and evaluated the effects of LF in alleviating LPS-induced intestinal immune barrier damage. Next, the related immune molecular mechanism on how LF exerted protective effects was investigated, through RNA-seq analyses of the mouse primary intestinal epithelial cells, and the specific genes were analyzed and screened out. Finally, the genes and their related immune pathway were validated in mRNA and protein levels; the portions of special immune cells (CD4+ T cells and CD8+ T cells) were also detected to further support our experimental results. Pharmacokinetic analyses demonstrated that the integrity of LF could reach mice stomach and intestine after oral gavage within 12 h, and the proper administration of LF should be the oral route. LF was proven to down-regulate the expression levels of inflammatory cytokines in both the primary intestinal epithelial cells and mice blood, especially LF without iron (Apo-LF), indicating LF alleviated infantile intestinal immune barrier damage induced by LPS. And through RNA-seq analyses of the mouse primary intestinal epithelial cells treated with LPS and LF, embryonic lethal abnormal vision Drosophila 1 (ELAVL1) was selected as one of the key genes, then the ELAVL1/PI3K/NF-κB pathway regulated by LF was verified to participate in the protection of infantile intestinal immune barrier damage in our study. Additionally, the ratio of blood CD4+/CD8+ T cells was significantly higher in the LF-treated mice than in the control mice, indicating that LF distinctly reinforced the overall immunity of infantile mice, further validating the strengthening bioactivity of LF on infantile intestinal immune barrier. In summary, LF was proven to alleviate LPS-induced intestinal immune barrier damage in young mice through regulating ELAVL1-related immune signaling pathways, which would expand current knowledge of the functions of bioactive proteins in foods within different research layers, as well as benefit preclinical and clinical researches in a long run.