Protein and Lipid Content of Milk Extracellular Vesicles: A Comparative Overview

Milk-derived exosomes as functional nanocarriers in wound healing: Mechanisms, applications, and future directions

Wound healing presents a significant challenge in healthcare, imposing substantial physiological and economic burdens. While traditional treatments and stem cell therapies have shown benefits, milk-derived exosomes (MDEs) offer distinct advantages as a cell-free therapeutic approach. MDEs, isolated from mammalian milk, are characterized by their biocompatibility, ease of acquisition, and high yield, making them a promising tool for enhancing wound repair. This review provides a comprehensive analysis of the composition, sources, and extraction methods of MDEs, with a focus on their therapeutic role in both acute and diabetic chronic wounds. MDEs facilitate wound healing through the delivery of bioactive molecules, modulating key processes such as inflammation, angiogenesis, and collagen synthesis. Their ability to regulate complex wound-healing pathways underscores their potential for widespread clinical application. This review highlights the importance of MDEs in advancing wound management and proposes strategies to optimize their use in regenerative medicine.

Isolation of bovine milk-derived extracellular vesicles via a capillary-channeled polymer (C-CP) fiber stationary phase

Extracellular vesicles (EVs) are released by all cell types into the extracellular environment. A subset of EVs, known as exosomes, range in size from 30 to 200 nm and are of biochemical interest due to their function as vehicles of intercellular communication. Their ability to transport proteinaceous species and genetic material at the cellular level makes them prime candidates as vectors in gene therapies. Focusing on biotherapeutics, bovine milk-derived extracellular vesicles (MDEVs) hold particular promise as an alternative to other exosome sources for therapeutics delivery. Bovine milk poses unique challenges due to the complex colloidal matrix, composed predominantly of fats and proteins like casein, which form micelles that exhibit exosome-like characteristics, specifically size and density. When faced with complex matrices like milk, conventional size/density-based isolation methods including ultracentrifugation and size exclusion chromatography struggle to provide high purity yields on practical time and cost scales. When paired with a stepwise hydrophobic interaction chromatography (HIC) gradient, polyester (PET) capillary-channeled polymer (C-CP) fibers in column and spin-down tips formats have been used effectively to isolate exosomes from highly diverse sources. Here, PET C-CP fiber columns are demonstrated to isolate MDEVs from pre-treated raw milk, yielding concentrations of 1.5 × 1010 particles mL⁻1 with purities of ~2 × 1010 EVs µg-1 protein in less than 20 min. The efficacy of the isolation process is verified by a suite of characterization methods. Implementing PET C-CP fiber columns for MDEV isolation addresses the challenges associated with conventional isolation methods, holding promise for scale-up towards therapeutic applications.

Integration of Macrogenomics and Metabolomics: Comprehensive Insights into the Effects of In Vitro Fermentation with Human Milk Exosomes on Infant Gut Microbiota

The role of human milk exosomes (HMEs) in maintaining infant intestinal health has attracted considerable attention, yet the mechanisms by which they regulate the infant gut microbiota remain to be elucidated. In this study, we constructed an in vitro fermentation model, combined with macrogenomics and nontargeted metabolomics technologies, to deeply analyze the effects of HMEs on the composition of intestinal microorganisms, the expression of functional genes, and the production of metabolites. It showed that HMEs significantly reduced the potential pathogenic bacteria like Escherichia coli, Klebsiella pneumoniae, Dysgonomonas capnocytophagoides, and Shigella flexneri, but increased Bacteroides fragilis and Bifidobacterium pseudocatenulatum. Moreover, HMEs promote key metabolic pathways including propionate and butyrate metabolism, glycolysis/glycogenesis, and amino acid metabolism. Consequently, beneficial intestinal metabolites such as short-chain fatty acids (SCFAs), amino acids, indoles, and secondary bile acids were elevated. It is speculated that HMEs may act as key signaling molecules or regulators to improve infant gut microecology.

Untargeted lipidomics reveals unique lipid signatures of extracellular vesicles from porcine colostrum and milk

Extracellular vesicles (EV) are membranous vesicles considered as significant players in cell-to-cell communication. Milk provides adequate nutrition, transfers immunity, and promotes neonatal development, and milk EV are suggested to play a crucial role in these processes. Milk samples were obtained on days 0, 7, and 14 after parturition from sows receiving either a standard diet (ω-6:ω-3 = 13:1) or a test diet enriched in ω-3 (ω-6:ω-3 = 4:1). EV were isolated using ultracentrifugation coupled with size exclusion chromatography, and characterized by nanoparticle tracking analysis, transmission electron microscopy, and assessment of EV markers via Western blotting. The lipidome was determined following a liquid chromatography-quadrupole time-of-flight mass spectrometry approach. Here, we show that different stages of lactation (colostrum vs mature milk) have a distinct extracellular vesicle lipidomic profile. The distinct lipid content can be further explored to understand and regulate milk EV functionalities and primordial for enabling their diagnostic and therapeutic potential.

Milk-derived extracellular vesicles and gut health

Milk is a nutrient-rich liquid produced by mammals, offering various health benefits due to its composition of proteins, fats, carbohydrates, vitamins, and minerals. Beyond traditional nutritional aspects, recent research has focused on extracellular vesicles (EVs) found in milk and their potential health benefits, especially for gastrointestinal (GI) health. Milk-derived EVs have been shown to influence gut microbiota, promote gut barrier integrity, support tissue repair and regeneration, modulate immune responses, and potentially aid in managing conditions like inflammatory bowel disease (IBD) and colorectal cancer. This review discusses the current understanding of milk-EVs' effects on gut health, highlighting their potential therapeutic applications and future research directions. These findings underscore the promising role of milk-derived EVs in advancing GI health and therapeutics, paving the way for innovative approaches in oral drug delivery and targeted treatments for GI disorders.

Characterization of the functional component in human milk and identification of the molecular mechanisms undergoing prematurity

BACKGROUND AND AIMS

Human milk (HM) is the earliest form of extrauterine communication between mother and infant, that could promote early programming. The aim of this study is to look for specific biological processes, particularly those undergoing prematurity, modulated by proteins and miRNAs of HM that could be implicated in growth and development.

METHODS

This is a prospective, observational, single center study in which we collected 48 human milk (HM) samples at two distinct stages of lactation: colostrum (first 72-96 h) and mature milk (at week 4 post-delivery) from mothers of very preterm newborns (<32 weeks) and term (≥37 and < 42 weeks). Qualitative and quantitative proteomic and transcriptomic analysis was done in our samples.

RESULTS

We performed isolation and characterization of HM extracellular vesicles (EVs) to carry out proteomic and transcriptomic analysis in colostrum (CM) and mature milk (MM). Proteomic analysis revealed a functional role of CM in immunological protection and MM in metabolic processes. TENA, TSP1 and OLF4, proteins with roles in immune response and inflammatory modulation, were upregulated in CM vs MM, particularly in preterm. HM modulation differed depending on gestational age (GA). The miRNAs identified in HM are implicated in structural functions, including growth and neurological development. miRNA-451a was differentially expressed between groups, and downregulated in preterm CM.

CONCLUSIONS

Because the particularities of each GA are reflected in the EVs content of HM, providing newborns with HM from their own mother is the optimal way for satisfying their specific needs. Although the role of the proteomic profile of CM and MM of different GA in relation to neurodevelopment has been previously described, this is the first study to show a complete functional characterization of HM (proteome, miRNA at the same time), unmasking the molecular mechanisms related to EVs signaling and their functional role in preterm.

A novel exosome-like nanovesicles from Cordyceps militaris potentiate immunomodulatory and anti-tumor effect by reprogramming macrophages

AIMS

Fungi-derived exosome-like nanovesicles (ENs) are emerging as a highly promising class of nanoparticles, particularly noted for their cost-effective production. However, their impact on immune regulation and their potential as anti-tumor agents need further exploration. Our study specifically focused on the investigation of the immunomodulatory and anti-tumor properties of ENs derived from Cordyceps militaris, an edible fungus that had achieved large-scale commercial production, referred to as CMDENs.

MAIN METHODS

The ENs of C. militaris were collected through ultra-high-speed centrifugation, followed by characterization of their physicochemical properties and contents. Subsequently, the biological distribution of these vesicles was investigated using in vivo fluorescence imaging experiments. Finally, the immune activation and polarization of macrophages were examined through both in vitro and in vivo experiments.

KEY FINDINGS

Herein, we presented the discovery of CMDENs that were rich in proteins, lipids, flavonoids and alkaloids. Immunomodulatory experiments conducted in vivo demonstrated that CMDENs exhibited protective effects against cyclophosphamide-induced immunosuppression in mice by significantly enhancing macrophage phagocytosis and peripheral blood immune cell counts. Moreover, CMDENs effectively induced the polarization of M0- and M2-like macrophages toward M1-like phenotype by activating MAPKs signaling pathway. Notably, CMDENs exhibited remarkable capabilities in inhibiting tumor growth by reprogramming tumor-associated macrophages and activating tumor-infiltrating T lymphocytes, without any observed toxicity in mice bearing tumors.

SIGNIFICANCE

Our research suggested that CMDENs possessed the potential to be explored as a nano-immunomodulatory agent for cancer.

Fingerprinting Breast Milk; insights into Milk Exosomics

Breast milk, often referred to as "liquid gold," is a complex biofluid that provides essential nutrients, immune factors, and developmental cues for newborns. Recent advancements in the field of exosome research have shed light on the critical role of exosomes in breast milk. Exosomes are nanosized vesicles that carry bioactive molecules, including proteins, lipids, nucleic acids, and miRNAs. These tiny messengers play a vital role in intercellular communication and are now being recognized as key players in infant health and development. This paper explores the emerging field of milk exosomics, emphasizing the potential of exosome fingerprinting to uncover valuable insights into the composition and function of breast milk. By deciphering the exosomal cargo, we can gain a deeper understanding of how breast milk influences neonatal health and may even pave the way for personalized nutrition strategies.

Food-derived extracellular vesicles in the human gastrointestinal tract: Opportunities for personalised nutrition and targeted therapeutics

Food-derived extracellular vesicles (FDEVs) such as those found in mammalian milk and plants are of great interest for both their health benefits and ability to act as biological nanocarriers. While the extracellular vesicle (EV) field is expanding rapidly to perform characterisation studies on FDEVs from plants, yeasts and bacteria, species-specific differences in EV uptake and function in the human gastrointestinal (GI) tract are poorly understood. Moreover, the effects of food processing on the EV surfaceome and intraluminal content also raises questions surrounding biological viability once consumed. Here, I present a case for increasing community-wide focus on understanding the cellular uptake of FDEVs from different animal, plant, yeast, and bacterial species and how this may impact their function in the human, which will have implications for human health and therapeutic strategies alike.

Toward the nanoscale chemical and physical probing of milk-derived extracellular vesicles using Raman and tip-enhanced Raman spectroscopy

Tip-enhanced Raman spectroscopy (TERS) is an advanced technique to perform local chemical analysis of the surface of a sample through the improvement of the sensitivity and the spatial resolution of Raman spectroscopy by plasmonic enhancement of the electromagnetic signal in correspondence with the nanometer-sized tip of an atomic force microscope (AFM). In this work, TERS is demonstrated to represent an innovative and powerful approach for studying extracellular vesicles, in particular bovine milk-derived extracellular vesicles (mEVs), which are nanostructures with considerable potential in drug delivery and therapeutic applications. Raman spectroscopy has been used to analyze mEVs at the micrometric and sub-micrometric scales to obtain a detailed Raman spectrum in order to identify the 'signature' of mEVs in terms of their characteristic molecular vibrations and, therefore, their chemical compositions. With the ability to improve lateral resolution, TERS has been used to study individual mEVs, demonstrating the possibility of investigating a single mEV selected on the surface of the sample and, moreover, analyzing specific locations on the selected mEV with nanometer lateral resolution. TERS potentially allows one to reveal local differences in the composition of mEVs providing new insights into their structure. Also, thanks to the intrinsic properties of TERS to acquire the signal from only the first few nanometers of the surface, chemical investigation of the lipid membrane in correspondence with the various locations of the selected mEV could be performed by analyzing the peaks of the Raman shift in the relevant range of the spectrum (2800-3000 cm-1). Despite being limited to mEVs, this work demonstrates the potential of TERS in the analysis of extracellular vesicles.

Milk-Derived Extracellular Vesicles: Biomedical Applications, Current Challenges, and Future Perspectives

Extracellular vesicles (EVs) are nano to-micrometer-sized sacs that are released by almost all animal and plant cells and act as intercellular communicators by transferring their cargos between the source and target cells. As a safe and scalable alternative to conditioned medium-derived EVs, milk-derived EVs (miEVs) have recently gained a great deal of popularity. Numerous studies have shown that miEVs have intrinsic therapeutic actions that can treat diseases and enhance human health. Additionally, they can be used as natural drug carriers and novel classes of biomarkers. However, due to the complexity of the milk, the successful translation of miEVs from benchtop to bedside still faces several unfilled gaps, especially a lack of standardized protocols for the isolation of high-purity miEVs. In this work, by comprehensively reviewing the bovine miEVs studies, we provide an overview of current knowledge and research on miEVs while highlighting their challenges and enormous promise as a novel class of theranostics. It is hoped that this study will pave the way for clinical applications of miEVs by addressing their challenges and opportunities.

Unraveling the Multifaceted Roles of Extracellular Vesicles: Insights into Biology, Pharmacology, and Pharmaceutical Applications for Drug Delivery

Extracellular vesicles (EVs) are nanoparticles released from various cell types that have emerged as powerful new therapeutic option for a variety of diseases. EVs are involved in the transmission of biological signals between cells and in the regulation of a variety of biological processes, highlighting them as potential novel targets/platforms for therapeutics intervention and/or delivery. Therefore, it is necessary to investigate new aspects of EVs' biogenesis, biodistribution, metabolism, and excretion as well as safety/compatibility of both unmodified and engineered EVs upon administration in different pharmaceutical dosage forms and delivery systems. In this review, we summarize the current knowledge of essential physiological and pathological roles of EVs in different organs and organ systems. We provide an overview regarding application of EVs as therapeutic targets, therapeutics, and drug delivery platforms. We also explore various approaches implemented over the years to improve the dosage of specific EV products for different administration routes.

Application of Milk Exosomes for Musculoskeletal Health: Talking Points in Recent Outcomes

Milk is a nutrient-rich food source, and among the various milks, breast milk is a nutrient source provided by mothers to newborns in many mammals. Exosomes are nano-sized membranous extracellular vesicles that play important roles in cell-to-cell communication. Exosomes originate from endogenous synthesis and dietary sources such as milk. Discovered through electron microscopy as floating vesicles, the existence of exosomes in human milk was confirmed owing to a density between 1.10 and 1.18 g/mL in a sucrose gradient corresponding to the known density of exosomes and detection of MHC classes I and II, CD63, CD81, and CD86 on the vesicles. To date, milk exosomes have been used for treating many diseases, including cancers, and are widely proposed as promising carriers for the delivery of chemotherapeutic agents. However, few studies on milk exosomes focus on geriatric health, especially sarcopenia and osteoporosis related to bone and muscle. Therefore, the present study focused on milk exosomes and their cargoes, which are potential candidates for dietary supplements, and when combined with drugs, they can be effective in treating musculoskeletal diseases. In this review, we introduce the basic concepts, including the definition, various sources, and cargoes of milk exosomes, and exosome isolation and characterization methods. Additionally, we review recent literature on the musculoskeletal system and milk exosomes. Since inflammation and oxidative stress underly musculoskeletal disorders, studies reporting the antioxidant and anti-inflammatory properties of milk exosomes are also summarized. Finally, the therapeutic potential of milk exosomes in targeting muscle and bone health is proposed.

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.

Milk-derived small extracellular vesicles: a new perspective on dairy nutrition

Milk contains bioactive compounds that have multiple essential benefits. Milk-derived small extracellular vesicles (M-sEVs) have emerged as novel bioactive milk components with various beneficial biological functions and broad applications. The M-sEVs from different mammalian sources have similar composition and bioactive functions. The digestive stability and biocompatibility of the M-sEVs provide a good foundation for their physiological functions. Evidence suggests that M-sEVs promote intestinal, immune, bone, neural, liver, and heart health and show therapeutic effects against cancer, indicating their potential for use in functional foods. In addition, M-sEVs can be developed as natural delivery carriers owing to their superior structural characteristics. Further studies are needed to elucidate the relationship between the specific components and functions of M-sEVs, standardize their extraction processes, and refine relevant clinical trials to advance the future applications of M-sEVs. This review summarizes the structure and composition of M-sEVs isolated from different milk sources and discusses several common extraction methods. Since the introduction of M-sEVs for digestion and absorption, studies have been conducted on their biological functions. Furthermore, we outline the theoretical industrial production route, potential application scenarios of M-sEVs, and the future perspectives of M-sEV research.