Oral nanomedicine for modulating immunity, intestinal barrier functions, and gut microbiome

β-Glucan-A promising immunocyte-targeting drug delivery vehicle: Superiority, applications and future prospects

Drug delivery technologies that could convert promising therapeutics into successful therapies have been under broad research for many years. Recently, β-glucans, natural-occurring polysaccharides extracted from many organism species such as yeast, fungi and bacteria, have attracted increasing attention to serve as drug delivery carriers. With their unique structure and innate immunocompetence, β-glucans are considered as promising carriers for targeting delivery especially when applied in the vaccine construction and oral administration of therapeutic agents. In this review, we focus on three types of β-glucans applied in the drug delivery system including yeast β-glucan, Schizophyllan and curdlan, highlighting the benefits of β-glucan based delivery system. We summarize how β-glucans as delivery vehicles have aided various therapeutics ranging from macromolecules including proteins, peptides and nucleic acids to small molecular drugs to reach desired cells or organs in terms of loading strategies. We also outline the challenges and future directions for developing the next generation of β-glucan based delivery systems.

Novel strategies for modulating the gut microbiome for cancer therapy

Recent advancements in genomics, transcriptomics, and metabolomics have significantly advanced our understanding of the human gut microbiome and its impact on the efficacy and toxicity of anti-cancer therapeutics, including chemotherapy, immunotherapy, and radiotherapy. In particular, prebiotics, probiotics, and postbiotics are recognized for their unique properties in modulating the gut microbiota, maintaining the intestinal barrier, and regulating immune cells, thus emerging as new cancer treatment modalities. However, clinical translation of microbiome-based therapy is still in its early stages, facing challenges to overcome physicochemical and biological barriers of the gastrointestinal tract, enhance target-specific delivery, and improve drug bioavailability. This review aims to highlight the impact of prebiotics, probiotics, and postbiotics on the gut microbiome and their efficacy as cancer treatment modalities. Additionally, we summarize recent innovative engineering strategies designed to overcome challenges associated with oral administration of anti-cancer treatments. Moreover, we will explore the potential benefits of engineered gut microbiome-modulating approaches in ameliorating the side effects of immunotherapy and chemotherapy.

Developing targeted antioxidant nanomedicines for ischemic penumbra: Novel strategies in treating brain ischemia-reperfusion injury

During cerebral ischemia-reperfusion conditions, the excessive reactive oxygen species in the ischemic penumbra region, resulting in neuronal oxidative stress, constitute the main pathological mechanism behind ischemia-reperfusion damage. Swiftly reinstating blood perfusion in the ischemic penumbra zone and suppressing neuronal oxidative injury are key to effective treatment. Presently, antioxidants in clinical use suffer from low bioavailability, a singular mechanism of action, and substantial side effects, severely restricting their therapeutic impact and widespread clinical usage. Recently, nanomedicines, owing to their controllable size and shape and surface modifiability, have demonstrated good application potential in biomedicine, potentially breaking through the bottleneck in developing neuroprotective drugs for ischemic strokes. This manuscript intends to clarify the mechanisms of cerebral ischemia-reperfusion injury and provides a comprehensive review of the design and synthesis of antioxidant nanomedicines, their action mechanisms and applications in reversing neuronal oxidative damage, thus presenting novel approaches for ischemic stroke prevention and treatment.

Opening the doors of precision medicine: novel tools to assess intestinal barrier in inflammatory bowel disease and colitis-associated neoplasia

Mounting evidence underscores the pivotal role of the intestinal barrier and its convoluted network with diet and intestinal microbiome in the pathogenesis of inflammatory bowel disease (IBD) and colitis-associated colorectal cancer (CRC). Moreover, the bidirectional association of the intestinal barrier with the liver and brain, known as the gut-brain axis, plays a crucial role in developing complications, including extraintestinal manifestations of IBD and CRC metastasis. Consequently, barrier healing represents a crucial therapeutic target in these inflammatory-dependent disorders, with barrier assessment predicting disease outcomes, response to therapy and extraintestinal manifestations.New advanced technologies are revolutionising our understanding of the barrier paradigm, enabling the accurate assessment of the intestinal barrier and aiding in unravelling the complexity of the gut-brain axis. Cutting-edge endoscopic imaging techniques, such as ultra-high magnification endocytoscopy and probe-based confocal laser endomicroscopy, are new technologies allowing real-time exploration of the 'cellular' intestinal barrier. Additionally, novel advanced spatial imaging technology platforms, including multispectral imaging, upconversion nanoparticles, digital spatial profiling, optical spectroscopy and mass cytometry, enable a deep and comprehensive assessment of the 'molecular' and 'ultrastructural' barrier. In this promising landscape, artificial intelligence plays a pivotal role in standardising and integrating these novel tools, thereby contributing to barrier assessment and prediction of outcomes.Looking ahead, this integrated and comprehensive approach holds the promise of uncovering new therapeutic targets, breaking the therapeutic ceiling in IBD. Novel molecules, dietary interventions and microbiome modulation strategies aim to restore, reinforce, or modulate the gut-brain axis. These advancements have the potential for transformative and personalised approaches to managing IBD.

Orally available dextran-aspirin nanomedicine modulates gut inflammation and microbiota homeostasis for primary colorectal cancer therapy

Reversing the aggravated immunosuppression hence overgrowth of colorectal cancer (CRC) caused by the gut inflammation and microbiota dysbiosis is pivotal for effective CRC therapy and metastasis inhibition. However, the low delivery efficiency and severe dose-limiting off-target toxicities caused by unsatisfied drug delivery systems remain the major obstacles in precisely modulating gut inflammation and microbiota in CRC therapy. Herein, a multifunctional oral dextran-aspirin nanomedicine (P3C-Asp) was utilized for oral treatment of primary CRC, as it could release salicylic acid (SA) while scavenging reactive oxygen species (ROS) and held great potential in modulating gut microbiota with prebiotic (dextran). Oral P3C-Asp retained in CRC tissues for over 12 h and significantly increased SA accumulation in CRC tissues over free aspirin (10.8-fold at 24 h). The enhanced SA accumulation and ROS scavenging of P3C-Asp cooperatively induced more potent inflammation relief over free aspirin, characterized as lower level of cyclooxygenase-2 and immunosuppressive cytokines. Remarkably, P3C-Asp promoted the microbiota homeostasis and notably increased the relative abundance of strengthening systemic anti-cancer immune response associated microbiota, especially lactobacillus and Akkermansia to 6.66- and 103- fold over the control group. Additionally, a demonstrable reduction in pathogens associated microbiota (among 96% to 79%) including Bacteroides could be detected. In line with our findings, inflammation relief along with enhanced abundance of lactobacillus was positively correlated with CRC inhibition. In primary CRC model, P3C-Asp achieved 2.1-fold tumor suppression rate over free aspirin, with an overall tumor suppression rate of 85%. Moreover, P3C-Asp cooperated with αPD-L1 further reduced the tumor weight of each mouse and extended the median survival of mice by 29 days over αPD-L1 alone. This study unravels the synergistic effect of gut inflammation and microbiota modulation in primary CRC treatment, and unlocks an unconventional route for immune regulation in TME with oral nanomedicine.

Mulberry Leaf Lipid Nanoparticles: a Naturally Targeted CRISPR/Cas9 Oral Delivery Platform for Alleviation of Colon Diseases

Oral treatment of colon diseases with the CRISPR/Cas9 system has been hampered by the lack of a safe and efficient delivery platform. Overexpressed CD98 plays a crucial role in the progression of ulcerative colitis (UC) and colitis-associated colorectal cancer (CAC). In this study, lipid nanoparticles (LNPs) derived from mulberry leaves are functionalized with Pluronic copolymers and optimized to deliver the CRISPR/Cas gene editing machinery for CD98 knockdown. The obtained LNPs possessed a hydrodynamic diameter of 267.2 nm, a narrow size distribution, and a negative surface charge (-25.6 mV). Incorporating Pluronic F127 into LNPs improved their stability in the gastrointestinal tract and facilitated their penetration through the colonic mucus barrier. The galactose end groups promoted endocytosis of the LNPs by macrophages via asialoglycoprotein receptor-mediated endocytosis, with a transfection efficiency of 2.2-fold higher than Lipofectamine 6000. The LNPs significantly decreased CD98 expression, down-regulated pro-inflammatory cytokines (TNF-α and IL-6), up-regulated anti-inflammatory factors (IL-10), and polarized macrophages to M2 phenotype. Oral administration of LNPs mitigated UC and CAC by alleviating inflammation, restoring the colonic barrier, and modulating intestinal microbiota. As the first oral CRISPR/Cas9 delivery LNP, this system offers a precise and efficient platform for the oral treatment of colon diseases.

Recent progress on engineered micro/nanomaterials mediated modulation of gut microbiota for treating inflammatory bowel disease

Inflammatory bowel disease (IBD) is a type of chronic recurrent inflammation disease that mainly includes Crohn's disease and ulcerative colitis. Currently, the treatments for IBD remain highly challenging, with clinical treatment drugs showing limited efficacy and adverse side effects. Thus, developing drug candidates with comprehensive therapeutic effects, high efficiency, and low toxicity is urgently needed. Recently, micro/nanomaterials have attracted considerable interest because of their bioavailability, multitarget and efficient effects on IBD. In addition, gut modulation plays a substantial role in restoring intestinal homeostasis. Therefore, efficient microbiota-based strategies modulating gut microenvironment have great potential in remarkably treating IBD. With the development of micro- and nanomaterials for the treatment of IBD and more in-depth studies of their therapeutic mechanisms, it has been found that these treatments also have a tendency to positively regulate the intestinal flora, resulting in an increase in the beneficial flora and a decrease in the level of pathogenic bacteria, thus regulating the composition of the intestinal flora to a normal state. In this review, we first present the interactions among the immune system, intestinal barrier, and gut microbiome. In addition, recent advances in administration routes and methods that positively arouse the regulation of intestinal flora for IBD using probiotics, prebiotics, and redox-active micro/nanomaterials have been reviewed. Finally, the key challenges and critical perspectives of gut microbiota-based micro/nanomaterial treatment are also discussed.

Superparamagnetic iron oxide nanoparticle regulates microbiota-gut-inner ear axis for hearing protection

Noise-induced hearing loss (NIHL) is a highly prevalent form of sensorineural hearing damage that has significant negative effects on individuals of all ages and there are no effective drugs approved by the US Food and Drug Administration. In this study, we unveil the potential of superparamagnetic iron oxide nanoparticle assembly (SPIOCA) to reshape the dysbiosis of gut microbiota for treating NIHL. This modulation inhibits intestinal inflammation and oxidative stress responses, protecting the integrity of the intestinal barrier. Consequently, it reduces the transportation of pathogens and inflammatory factors from the bloodstream to the cochlea. Additionally, gut microbiota-modulated SPIOCA-induced metabolic reprogramming in the gut-inner ear axis mainly depends on the regulation of the sphingolipid metabolic pathway, which further contributes to the restoration of hearing function. Our study confirms the role of the microbiota-gut-inner ear axis in NIHL and provides a novel alternative for the treatment of NIHL and other microbiota dysbiosis-related diseases.

Size effect of mesoporous silica nanoparticles on regulating the immune effect of oral influenza split vaccine

Mucosal immunization is a powerful weapon against viral infection. In this paper, large pore mesoporous silica nanoparticles (LMSN) with different particle sizes were synthesized for loading influenza split vaccine (SV) to explore the effect of nanoparticle sizes on mucosal immunization and adjuvant efficacy. Interestingly, it was found that among the three particle sizes of nanoparticles, only LMSN-M with around 250 nm could significantly enhance the mucosal immune effect of SV, possessing adjuvant effect. The results indicated that particle size affected the adjuvant effect of LMSN. There was no apparent difference in vaccine loading capacity of LMSN with different particle sizes, but the release of SV depended on the pore length of LMSN. The adjuvant effect of LMSN-M was attributed to its higher cellular uptake performance, intestine absorption and transport efficiency, and the ability to stimulate the maturation of dendritic cells. Simultaneously, compared with LMSN-S and LMSN-L, the more retention of LMSN-M in mesenteric lymph nodes increased the chance of interaction between vaccine and immune system, resulting in the enhanced immunity. This is the first time to study the impact of particle size of LMSN adjuvant on improving mucosal immunity of oral influenza vaccine, and the present work provides a scientific reference for adjuvant design of oral vaccine.

Interactions between nanoparticles and lymphatic systems: Mechanisms and applications in drug delivery

The lymphatic system has garnered significant attention in drug delivery research due to the advantages it offers, such as enhancing systemic exposure and enabling lymph node targeting for nanomedicines via the lymphatic delivery route. The journey of drug carriers involves transport from the administration site to the lymphatic vessels, traversing the lymph before entering the bloodstream or targeting specific lymph nodes. However, the anatomical and physiological barriers of the lymphatic system play a pivotal role in influencing the behavior and efficiency of carriers. To expedite research and subsequent clinical translation, this review begins by introducing the composition and classification of the lymphatic system. Subsequently, we explore the routes and mechanisms through which nanoparticles enter lymphatic vessels and lymph nodes. The review further delves into the interactions between nanomedicine and body fluids at the administration site or within lymphatic vessels. Finally, we provide a comprehensive overview of recent advancements in lymphatic delivery systems, addressing the challenges and opportunities inherent in current systems for delivering macromolecules and vaccines.

Readily Available Oral Prebiotic Protein Reactive Oxygen Species Nanoscavengers for Synergistic Therapy of Inflammation and Fibrosis in Inflammatory Bowel Disease

A significant gap exists in the demand for safe and effective drugs for inflammatory bowel disease (IBD), and its associated intestinal fibrosis. As oxidative stress plays a central role in the pathogenesis of IBD, astaxanthin (AST), a good antioxidant with high safety, holds promise for treating IBD. However, the application of AST is restricted by its poor solubility and easy oxidation. Herein, different protein-based nanoparticles (NPs) are fabricated for AST loading to identify an oral nanovehicle with potential clinical applicability. Through systematic validation via molecular dynamics simulation and in vitro characterization of properties, whey protein isolate (WPI)-driven NPs using a simple preparation method without the need for cross-linking agents or emulsifiers were identified as the optimal carrier for oral AST delivery. Upon oral administration, the WPI-driven NPs, benefiting from the intrinsic pH sensitivity and mucoadhesive properties, effectively shielded AST from degradation by gastric juices and targeted release of AST at intestinal lesion sites. Additionally, the AST NPs displayed potent therapeutic efficacy in both dextran sulfate sodium (DSS)-induced acute colitis and chronic colitis-associated intestinal fibrosis by ameliorating inflammation, oxidative damage, and intestinal microecology. In conclusion, the AST WPI NPs hold a potential therapeutic value in treating inflammation and fibrosis in IBD.

Mechanistic Investigation of Enzyme Triggered Release from a Xyloglucan Matrix Tablet for Controlled Colonic Drug Delivery

The objective of this study was to investigate the mechanisms underlying drug release from a controlled colonic release (CCR) tablet formulation based on a xyloglucan polysaccharide matrix and identify the factors that control the rate of release for the purpose of fundamentally substantiating the concept and demonstrating its robustness for colonic drug delivery. Previous work demonstrated in vitro limited release of 5-aminosalicylic acid (5-ASA) and caffeine from these tablets in small intestinal environment and significant acceleration of release by xyloglucanase, an enzyme of the colonic microbiome. Targeted colonic drug delivery was verified in an animal study in vivo. In the present work, interaction of the xyloglucan matrix tablets with aqueous dissolution media containing xyloglucanase was found to lead to the spontaneous formation of a hydrated highly viscous gummy layer at the surface of the matrix which had a reduced drug content compared to the underlying regions and persisted with a nearly constant thickness that was inversely correlated to the enzyme concentration throughout the duration of the release process. Enzymatic hydrolysis of xyloglucan was determined to take place at the surface of the matrix leading to matrix erosion and a relation for the rate of enzymatic reaction as a function of bulk enzyme concentration and the concentration of dissolved xyloglucan in the gummy layer was derived. A mathematical model was developed encompassing aqueous medium ingress, matrix metamorphosis due to xyloglucan dissolution and matrix swelling, enzymatic hydrolysis of the polysaccharide and concomitant drug release due to matrix erosion and simultaneous drug diffusion. The model was fitted to data of reducing sugar equivalents in the medium reflecting matrix erosion and released drug amount. Enzymatic reaction parameters and reasonable values of medium ingress velocity, xyloglucan dissolution rate constant and drug diffusion coefficient were deduced that provided an adequate approximation of the data. Erosion was shown to be the overwhelmingly dominant drug release mechanism while the role of diffusion marginally increased at low enzyme concentration and high drug solubility. Changing enzyme concentration had a rather weak effect on matrix erosion and drug release rate as demonstrated by model simulations supported by experimental data, while xyloglucan dissolution was slow and had a stronger effect on the rate of the process. Therefore, reproducible colonic drug delivery not critically influenced by inter- and intra-individual variation of microbial enzyme activity may be projected.

Influence of Gut Microbiota-Mediated Immune Regulation on Response to Chemotherapy

The involvement of the gut microbiota in anti-cancer treatment has gained increasing attention. Alterations to the structure and function of the gut bacteria are important factors in the development of cancer as well as the efficacy of chemotherapy. Recent studies have confirmed that the gut microbiota and related metabolites influence the pharmacological activity of chemotherapeutic agents through interactions with the immune system. This review aims to summarize the current knowledge of how malignant tumor and chemotherapy affect the gut microbiota, how the gut microbiota regulates host immune response, and how interactions between the gut microbiota and host immune response influence the efficacy of chemotherapy. Recent advances in strategies for increasing the efficiency of chemotherapy based on the gut microbiota are also described. Deciphering the complex homeostasis maintained by the gut microbiota and host immunity provides a solid scientific basis for bacterial intervention in chemotherapy.

Immunomodulatory nanomedicine for osteoporosis: Current practices and emerging prospects

Osteoporosis results from the disruption of the balance between bone resorption and bone formation. However, classical anti-osteoporosis drugs exhibit several limitations in clinical applications, such as multiple adverse reactions and poor therapeutic effects. Therefore, there is an urgent need for alternative treatment strategies. With the evolution of immunomodulatory nanomedicine, a variety of nanomaterials have been designed for anti-osteoporosis treatment, offering prospects of minimal adverse reactions, enhanced bone induction, and high osteogenic activity. This review initially provides a brief overview of the fundamental principles of bone reconstruction, current osteogenic clinical methods in osteoporosis treatment, and the significance of osteogenic-angiogenic coupling, laying the groundwork for understanding the pathophysiology and therapeutics of osteoporosis. Subsequently, the article emphasizes the relationship between bone immunity and osteogenesis-angiogenesis coupling and provides a detailed analysis of the application of immunomodulatory nanomedicines in the treatment of osteoporosis, including various types of nanomaterials and their integration with carrier biomaterials. Importantly, we discuss the potential of some emerging strategies in immunomodulatory nanomedicine for osteoporosis treatment. This review introduces the innovative applications of immunomodulatory nanomedicine in the treatment of osteoporosis, aiming to serve as a reference for the application of immunomodulatory nanomedicine strategies in osteoporosis treatment. STATEMENT OF SIGNIFICANCE: Osteoporosis, as one of the most prevalent skeletal disorders, poses a significant threat to public health. To date, conventional anti-osteoporosis strategies have been limited in efficacy and plagued with numerous side effects. Fortunately, with the advancement of research in osteoimmunology and nanomedicine, strategies integrating these two fields show great promise in combating osteoporosis. Nanomedicine with immunomodulatory properties exhibits enhanced efficiency, prolonged effectiveness, and increased safety. However, as of now, there exists no comprehensive review amalgamating immunomodulation with nanomedicine to delineate the progress of immunomodulatory nanomedicine in osteoporosis treatment, as well as the future direction of this strategy.

Oral administration of PEDV-dissolved Alg-CS gel induces high and sustained mucosal immunity in mice

Porcine epidemic diarrhea (PED) is a serious disease in piglets that leads to high mortality. An effective measure that provides higher IgA levels in the intestine and milk is required to decrease losses. Porcine epidemic diarrhea virus (PEDV) was dissolved in calcium alginate (Alg) and combined with chitosan (CS) via electrostatic interactions between cationic chitosan and anionic alginate to create a porous gel (Alg-CS+PEDV). The gel was used to immunize mice orally or in combination with subcutaneous injections of inactivated PEDV vaccine. At 12 and 24 days after immunization, levels of IgA and IgG in Alg-CS+PEDV were higher than with normal PEDV oral administration. At 24 days after immunization, the concentration of IFN-γ in Alg-CS+PEDV was higher than with normal PEDV oral administration. Furthermore, oral administration combining subcutaneous immunization induced higher levels of IgG and IgA than oral administration alone. Our study provides a new method for the preparation and administration of oral vaccines to achieve enhanced mucosal immunity against PEDV.

Microbiome Dynamics: A Paradigm Shift in Combatting Infectious Diseases

Infectious diseases have long posed a significant threat to global health and require constant innovation in treatment approaches. However, recent groundbreaking research has shed light on a previously overlooked player in the pathogenesis of disease-the human microbiome. This review article addresses the intricate relationship between the microbiome and infectious diseases and unravels its role as a crucial mediator of host-pathogen interactions. We explore the remarkable potential of harnessing this dynamic ecosystem to develop innovative treatment strategies that could revolutionize the management of infectious diseases. By exploring the latest advances and emerging trends, this review aims to provide a new perspective on combating infectious diseases by targeting the microbiome.

Therapeutic application and potential mechanism of plant-derived extracellular vesicles in inflammatory bowel disease

BACKGROUND

Plant-derived extracellular vesicles (PDEVs) are membrane vesicles characterized by a phospholipid bilayer as the basic skeleton that is wrapped by various functional components of proteins and nucleic acids. An increasing number of studies have confirmed that PDEVs can be a potential treatment of inflammatory bowel disease (IBD) and can, to some extent, compensate for the limitations of existing therapies.

AIM OF REVIEW

This review summarizes the recent advances and potential mechanisms underlying PDEVs obtained from different sources to alleviate IBD. In addition, the review discusses the possible applications and challenges of PDEVs, providing a theoretical basis for exploring novel and practical therapeutic strategies for IBD.

KEY SCIENTIFIC CONCEPTS OF REVIEW

In IBD, the crosstalk mechanism of PDEVs may regulate the intestinal microenvironment homeostasis, especially immune responses, the intestinal barrier, and the gut microbiota. In addition, drug loading enhances the therapeutic potential of PDEVs, particularly regarding improved tissue targeting and stability. In the future, not only immunotherapy based on PDEVs may be an effective treatment for IBD, but also the intestinal barrier and intestinal microbiota will be a new direction for the treatment of IBD.

Attenuation of Chronic Inflammation in Intestinal Organoids with Graphene Oxide-Mediated Tumor Necrosis Factor-α_Small Interfering RNA Delivery

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract with a complex and multifactorial etiology, making it challenging to treat. While recent advances in immunomodulatory biologics, such as antitumor necrosis factor-α (TNF-α) antibodies, have shown moderate success, systemic administration of antibody therapeutics may lead to several adverse effects, including the risk of autoimmune disorders due to systemic cytokine depletion. Transient RNA interference using exogenous short interfering RNA (siRNA) to regulate target gene expression at the transcript level offers an alternative to systemic immunomodulation. However, siRNAs are susceptible to premature degradation and have poor cellular uptake. Graphene oxide (GO) nanoparticles have been shown to be effective nanocarriers for biologics due to their reduced cytotoxicity and enhanced bioavailability. In this study, we evaluate the therapeutic efficacy of GO mediated TNF-α_siRNA using in vitro models of chronic inflammation generated by treating murine small intestines (enteroids) and large intestines (colonoids) with inflammatory agents IL-1β, TNF-α, and LPS. The organotypic mouse enteroids and colonoids developed an inflammatory phenotype similar to that of IBD, characterized by impaired epithelial homeostasis and an increased production of inflammatory cytokines such as TNF-α, IL-1β, and IL-6. We assessed siRNA delivery to these inflamed organoids using three different GO formulations. Out of the three, small-sized GO with polymer and dendrimer modifications (smGO) demonstrated the highest transfection efficiency, which led to the downregulation of inflammatory cytokines, indicating an attenuation of the inflammatory phenotype. Moreover, the transfection efficiency and inflammation-ameliorating effects could be further enhanced by increasing the TNF-α_siRNA/smGO ratio from 1:1 to 3:1. Overall, the results of this study demonstrate that ex vivo organoids with disease-specific phenotypes are invaluable models for assessing the therapeutic potential of nanocarrier-mediated drug and biologic delivery systems.

Peptidome comparison on the immune regulation effects of different casein fractions in a cyclophosphamide mouse model

The protein composition of human milk plays a crucial role in infant formula milk powder formulation. Notably, significant differences exist between bovine casein and human milk casein. Previous studies have shown that casein hydrolysates could enhance immune function; however, gastrointestinal dyspepsia in infants affects the type and function of peptides. Therefore, the present study used peptidomics to sequence and analyze hydrolyzed peptides from different casein fractions. Additionally, animal experiments were conducted to assess the functionality of these casein fractions and elucidate their differences. The results revealed variations in peptide composition among the different casein fractions of formula milk powder. Interestingly, milk powder formulated with both β- and κ-casein (BK) exhibited significant enrichment of peptides related to the immune system. Moreover, the BK group significantly alleviated immune organ damage in cyclophosphamide-treated mice and regulated serum levels of pro-inflammatory and anti-inflammatory factors. Furthermore, feeding different casein fractions influenced the intestinal microflora of cyclophosphamide-treated mice, with the BK group mitigating the changes caused by cyclophosphamide. In conclusion, the findings suggest that BK formula in milk powder has the potential to positively enhance immunity. This study provides a robust theoretical basis for human-emulsified formula milk powder development.

Epitope-based precision immunotherapy of Type 1 diabetes

Antigen-specific immunotherapies (ASITs) address important clinical needs in treating autoimmune diseases. However, Type 1 diabetes is a heterogeneous disease wherein patient characteristics influence responsiveness to ASITs. Targeting not only disease-relevant T cell populations, but also specific groups of patients using precision medicine is a new goal toward achieving effective treatment. HLA-restricted peptides provide advantages over protein as antigens, however, methods for profiling antigen-specific T cells need to improve in sensitivity, depth, and throughput to facilitate epitope selection. Delivery approaches are highly diverse, illustrating the many ways relevant antigen-presenting cell populations and anatomical locations can be targeted for tolerance induction. The role of persistence of antigen presentation in promoting durable antigen-specific tolerance requires further investigation. Based on the outcome of ASIT trials, the field is moving toward using patient-specific variations to improve efficacy, but challenges still lie on the path to delivering more effective and safer treatment to the T1D patient population.

Oral nanomedicine biointeractions in the gastrointestinal tract in health and disease

Oral administration is the preferred route of administration based on the convenience for and compliance of the patient. Oral nanomedicines have been developed to overcome the limitations of free drugs and overcome gastrointestinal (GI) barriers, which are heterogeneous across healthy and diseased populations. This review aims to provide a comprehensive overview and comparison of the oral nanomedicine biointeractions in the gastrointestinal tract (GIT) in health and disease (GI and extra-GI diseases) and highlight emerging strategies that exploit these differences for oral nanomedicine-based treatment. We introduce the key GI barriers related to oral delivery and summarize their pathological changes in various diseases. We discuss nanomedicine biointeractions in the GIT in health by describing the general biointeractions based on the type of oral nanomedicine and advanced biointeractions facilitated by advanced strategies applied in this field. We then discuss nanomedicine biointeractions in different diseases and explore how pathological characteristics have been harnessed to advance the development of oral nanomedicine.

Oral Immunotherapy Reshapes Intestinal Immunosuppression via Metabolic Reprogramming to Enhance Systemic Anti-Tumor Immunity

Tumor immunotherapy offers a new paradigm to treat cancer; however, the existing regimens are accompanied by the dilemma of insufficient therapeutic outcomes and off-target adverse effects. The intestinal immune system contains a bulk of immune cells, which can be important contributors to the maintenance of systemic immune homeostasis. However, manipulating intestinal immunity to achieve systemic anti-tumor immunity is extremely challenging. Here, an oral immunotherapy strategy is reported using immune-enhancing fullerenes (IEF) that can reinvigorate anti-tumor immunity via immune cell-metabolic reprogramming of intestinal immune cells. Findings show that IEF can remodel anti-inflammatory macrophages into tumor-killing macrophages by regulating the energy metabolism pathway from oxidative phosphorylation (OXPHOS) to glycolysis. Consequently, IEF can reprogram the immunosuppressive intestinal immunity and enhance sys temic immunity in vivo, thereby boosting anti-tumor immunity and converting "cold" tumors into "hot" tumors. Oral immunotherapy strategy, modulating autoimmune cells in the intestine and achieving systemic anti-tumor immunity, can ensure safe and efficient tumor immunotherapy.

Light-driven micro/nanomotors in biomedical applications

Nanotechnology brings hope for targeted drug delivery. However, most current drug delivery systems use passive delivery strategies with limited therapeutic efficiency. Over the past two decades, research on micro/nanomotors (MNMs) has flourished in the biomedical field. Compared with other driven methods, light-driven MNMs have the advantages of being reversible, simple to control, clean, and efficient. Under light irradiation, the MNMs can overcome several barriers in the body and show great potential in the treatment of various diseases, such as tumors, and gastrointestinal, cardiovascular and cerebrovascular diseases. Herein, the classification and mechanism of light-driven MNMs are introduced briefly. Subsequently, the applications of light-driven MNMs in overcoming physiological and pathological barriers in the past five years are highlighted. Finally, the future prospects and challenges of light-driven MNMs are discussed as well. This review will provide inspiration and direction for light-driven MNMs to overcome biological barriers in vivo and promote the clinical application of light-driven MNMs in the biomedical field.

Machine learning approach reveals microbiome, metabolome, and lipidome profiles in type 1 diabetes

INTRODUCTION

Type 1 diabetes (T1D) is a complex disorder influenced by genetic and environmental factors. The gut microbiome, the serum metabolome, and the serum lipidome have been identified as key environmental factors contributing to the pathophysiological mechanisms of T1D.

OBJECTIVES

We aimed to explore the gut microbiota, serum metabolite, and serum lipid signatures in T1D patients by machine learning.

METHODS

We evaluated 137 individuals in a cross-sectional cohort involving 38 T1D patients, 38 healthy controls, and 61 T1D patients for validation. We characterized gut microbiome, serum metabolite, and serum lipid profiles with machine learning approaches (logistic regression, support vector machine, Gaussian naive Bayes, and random forest).

RESULTS

The machine learning approaches using the microbiota composition did not accurately diagnose T1D (model accuracy = 0.7555), while the accuracy of the model using the metabolite composition was 0.9333. Based on the metabolite composition, 3-hydroxybutyric acid and 9-oxo-ode (area under curve = 0.70 and 0.67, respectively, both increased in T1D) were meaningful overlap metabolites screened by multiple bioinformatics methods. We confirmed the biological relevance of the microbiome, metabolome, and lipidome features in the validation group.

CONCLUSION

By using machine learning algorithms and multi-omics, we demonstrated that T1D patients are associated with altered microbiota, metabolite, and lipidomic signatures or functions.

Mechanisms by which the intestinal microbiota affects gastrointestinal tumours and therapeutic effects

The intestinal microbiota is considered to be a forgotten organ in human health and disease. It maintains intestinal homeostasis through various complex mechanisms. A significant body of research has demonstrated notable differences in the gut microbiota of patients with gastrointestinal tumours compared to healthy individuals. Furthermore, the dysregulation of gut microbiota, metabolites produced by gut bacteria, and related signal pathways can partially explain the mechanisms underlying the occurrence and development of gastrointestinal tumours. Therefore, this article summarizes the latest research progress on the gut microbiota and gastrointestinal tumours. Firstly, we provide an overview of the composition and function of the intestinal microbiota and discuss the mechanisms by which the intestinal flora directly or indirectly affects the occurrence and development of gastrointestinal tumours by regulating the immune system, producing bacterial toxins, secreting metabolites. Secondly, we present a detailed analysis of the differences of intestinal microbiota and its pathogenic mechanisms in colorectal cancer, gastric cancer, hepatocellular carcinoma, etc. Lastly, in terms of treatment strategies, we discuss the effects of the intestinal microbiota on the efficacy and toxic side effects of chemotherapy and immunotherapy and address the role of probiotics, prebiotics, FMT and antibiotic in the treatment of gastrointestinal tumours. In summary, this article provides a comprehensive review of the pathogenic mechanisms of and treatment strategies pertaining to the intestinal microbiota in patients with gastrointestinal tumours. And provide a more comprehensive and precise scientific basis for the development of microbiota-based treatments for gastrointestinal tumours and the prevention of such tumours.

Ginseng Stem-and-Leaf Saponins Mitigate Chlorpyrifos-Evoked Intestinal Toxicity In Vivo and In Vitro: Oxidative Stress, Inflammatory Response and Apoptosis

In recent years, the phenomenon of acute poisoning and organ damage caused by organophosphorus pesticides (OPs) has been a frequent occurrence. Chlorpyrifos (CPF) is one of the most widely used organophosphorus pesticides. The main active components of ginseng stems and leaves are total ginseng stem-and-leaf saponins (GSLSs), which have various biological effects, including anti-inflammatory, antioxidant and anti-tumor activities. We speculate that these could have great potential in the treatment of severe diseases and the relief of organophosphorus-pesticide-induced side effects; however, their mechanism of action is still unknown. At present, our work aims to evaluate the effects of GSLSs on the antioxidation of CPF in vivo and in vitro and their potential pharmacological mechanisms. Mice treated with CPF (5 mg/kg) showed severe intestinal mucosal injury, an elevated diamine oxidase (DAO) index, the decreased expression of occlusive protein-1 (ZO-1) and occlusive protein, an impaired intestinal mucosal oxidation system and intestinal villi relaxation. In addition, chlorpyrifos exposure significantly increased the contents of the inflammatory factor TNF-α and the oxidative-stress-related indicators superoxide dismutase (SOD), catalase (CAT), glutathione SH (GSH), glutathione peroxidase (GSH-PX), reactive oxygen species (ROS) and total antioxidant capacity (T-AOC); elevated the level of lipid peroxide malondialdehyde (MDA); reversed the expression of Bax and caspase; and activated NF-κB-related proteins. Interestingly, GSLS supplementation at doses of 100 and 200 mg/kg significantly reversed these changes after treatment. Similar results were observed in cultured RAW264.7 cells. Using flow cytometry, Hoechst staining showed that GSLSs (30 μg/mL, 60 μg/mL) could improve the cell injury and apoptosis caused by CPF and reduce the accumulation of ROS in cells. In conclusion, GSLSs play a protective role against CPF-induced enterotoxicity by inhibiting NF-κB-mediated apoptosis and alleviating oxidative stress and inflammation.

The intestinal mucosal barrier - A key player in rheumatoid arthritis?

Rheumatoid arthritis (RA) is a recurrent chronic autoimmune disease, which is not only difficult to treat, but also has a great adverse impact on the physical and mental health of patients. The intestinal mucosa barrier has some relationship with RA and it consists of mechanical barrier, chemical barrier, immune barrier, and microflora barrier. It is a dynamic system that contributes to the stability of the intestinal environment by regulating the absorption of relevant substances from the lumen into the circulation, while limiting the passage of harmful substances. This article summarizes the connection between the intestinal mucosa barrier and RA, and proposes the role of relevant Chinese medicines on RA from the point of improving barriers, to provide new perspectives on the pathogenesis and therapeutic strategies of RA.

Bioinspired fine-tuning of the mechanical rigidity of SNEDDS for the efficient crossing of multiple gastrointestinal barriers

Nanoproperties, such as size, charge, and rigidity, have been demonstrated to be crucial for nanovehicles to overcome numerous gastrointestinal obstacles. However, the facile approach of modifying the rigidity of nanovehicles remains scarce, limiting understanding of how rigidity impacts their oral delivery. Inspired by the fact that cellular phospholipid content regulates plasma membrane rigidity, the rigidity of self-nanoemulsifiying drug delivery system (SNEDDS) could be fine-tuned via phosphocholine content while their size and zeta potential remain unchanged, using insulin as a model drug. Notably, soft SNEDDS exerted longer gastrointestinal transit time, higher drug release rate, stronger gastrointestinal stability and relatively lower mucus permeation but superior epithelial transcytosis than their hard counterparts in a macropinocytosis-dependent manner. The rigidity-related enhanced transcytosis was attributed to improved endocytosis, lysosome escape capability and exocytosis. Rats with type 1 diabetes exhibited greater oral insulin absorption and blood glucose lowering effect with soft SNEDDS. This study demonstrated the regulatory role of phospholipids in nanovehicle rigidity, which could help develop mechanically optimized nanomedicines in the future.

Six Weeks of Supplementation with Bovine Colostrum Effectively Reduces URTIs Symptoms Frequency and Gravity for Up to 20 Weeks in Pre-School Children

Bovine colostrum is considered to provide anti-infective protection. Here, we present the first randomized controlled trial (RCT) aimed at assessing the preventive use of colostrum against upper respiratory tract infections (URTIs) in healthy pre-school children. We analyzed 57 children-35 in the colostrum (COL-dried bovine colostrum) and 22 in the placebo (PBO-dried whey) group, who received these substances as follows: first 15 days 2 × 500 mg and then 30 days 1 × 500 mg. The reporting on the children's health status, specifically on the frequency and gravity of URTI symptoms and abdominal side effects, was performed via an online survey. The influence of colostrum on the frequency of days with URTI symptoms remained significant until the 20th week of observation and reached 31% of median reduction. The median reduction reached 37% when the gravity of symptoms was analyzed. When we grouped symptomatic days into episodes of second gravity level, the reduction in their frequency was even larger (50%) and lasted until the end of the trial (21 weeks). No significant side effects, especially abdominal, were reported during the trial. Colostrum supplementation in pre-school children is well tolerated, safe and provides protection from frequency of URTIs and their gravity.

Cracking the intestinal lymphatic system window utilizing oral delivery vehicles for precise therapy

Oral administration is preferred over other drug delivery methods due to its safety, high patient compliance, ease of ingestion without discomfort, and tolerance of a wide range of medications. However, oral drug delivery is limited by the poor oral bioavailability of many drugs, caused by extreme conditions and absorption challenges in the gastrointestinal tract. This review thoroughly discusses the targeted drug vehicles to the intestinal lymphatic system (ILS). It explores the structure and physiological barriers of the ILS, highlighting its significance in dietary lipid and medication absorption and transport. The review presents various approaches to targeting the ILS using spatially precise vehicles, aiming to enhance bioavailability, achieve targeted delivery, and reduce first-pass metabolism with serve in clinic. Furthermore, the review outlines several methods for leveraging these vehicles to open the ILS window, paving the way for potential clinical applications in cancer treatment and oral vaccine delivery. By focusing on targeted drug vehicles to the ILS, this article emphasizes the critical role of these strategies in improving therapeutic efficacy and patient outcomes. Overall, this article emphasizes the critical role of targeted drug vehicles to the ILS and the potential impact of these strategies on improving therapeutic efficacy and patient outcomes.

Recent progress of micro/nanomotors to overcome physiological barriers in the gastrointestinal tract

Oral administration is a convenient administration route for gastrointestinal disease therapy with good patient compliance. But the nonspecific distribution of the oral drugs may cause serious side effects. In recent years, oral drug delivery systems (ODDS) have been applied to deliver the drugs to the gastrointestinal disease sites with decreased side effects. However, the delivery efficiency of ODDS is tremendously limited by physiological barriers in the gastrointestinal sites, such as the long and complex gastrointestinal tract, mucus layer, and epithelial barrier. Micro/nanomotors (MNMs) are micro/nanoscale devices that transfer various energy sources into autonomous motion. The outstanding motion characteristics of MNMs inspired the development of targeted drug delivery, especially the oral drug delivery. However, a comprehensive review of oral MNMs for the gastrointestinal diseases therapy is still lacking. Herein, the physiological barriers of ODDS were comprehensively reviewed. Afterward, the applications of MNMs in ODDS for overcoming the physiological barriers in the past 5 years were highlighted. Finally, future perspectives and challenges of MNMs in ODDS are discussed as well. This review will provide inspiration and direction of MNMs for the therapy of gastrointestinal diseases, pushing forward the clinical application of MNMs in oral drug delivery.

Biocompatible smart micro/nanorobots for active gastrointestinal tract drug delivery

INTRODUCTION

Oral delivery is the most commonly used route of drug administration owing to good patient compliance. However, the gastrointestinal (GI) tract contains multiple physiological barriers that limit the absorption efficiency of conventional passive delivery systems resulting in a low drug concentration reaching the diseased sites. Micro/nanorobots can convert energy to self-propulsive force, providing a novel platform to actively overcome GI tract barriers for noninvasive drug delivery and treatment.

AREAS COVERED

In this review, we first describe the microenvironments and barriers in the different compartments of the GI tract. Afterward, the applications of micro/nanorobots to overcome GI tract barriers for active drug delivery are highlighted and discussed. Finally, we summarize and discuss the challenges and future prospects of micro/nanorobots for further clinical applications.

EXPERT OPINION

Micro/nanorobots with the ability to autonomously propel themselves and to load, transport, and release payloads on demand are ideal carriers for active oral drug delivery. Although there are many challenges to be addressed, micro/nanorobots have great potential to introduce a new era of drug delivery for precision therapy.

pH-triggered dynamic erosive small molecule chlorambucil nano-prodrugs mediate robust oral chemotherapy

Currently, the dynamic erosive small molecule nano-prodrug is of great demand for oral chemotherapy, owing to its precise structure, high drug loading and improved oral bioavailability via overcoming various physiologic barriers in gastrointestinal tract, blood circulation and tumor tissues compared to other oral nanomedicines. Herein, this work highlights the successful development of pH-triggered dynamic erosive small molecule nano-prodrugs based on in vivo significant pH changes, which are synthesized via amide reaction between chlorambucil and star-shaped ortho esters. The precise nano-prodrugs exhibit extraordinarily high drug loading (68.16%), electric neutrality, strong hydrophobicity, and dynamic large-to-small size transition from gastrointestinal pH to tumoral pH. These favorable physicochemical properties can effectively facilitate gastrointestinal absorption, blood circulation stability, tumor accumulation, cellular uptake, and cytotoxicity, therefore achieving high oral relative bioavailability (358.72%) and significant tumor growth inhibition while decreasing side effects. Thus, this work may open a new avenue for robust oral chemotherapy attractive for clinical translation.

Challenges and opportunities in delivering oral peptides and proteins

INTRODUCTION

Rapid advances in bioengineering enable the use of complex proteins as therapeutic agents to treat diseases. Compared with conventional small molecule drugs, proteins have multiple advantages, including high bioactivity and specificity with low toxicity. Developing oral dosage forms with active proteins is a route to improve patient compliance and significantly reduce production costs. However, the gastrointestinal environment remains a challenge to this delivery path due to enzymatic degradation, low permeability, and weak absorption, leading to reduced delivery efficiency and poor clinical outcomes.

AREAS COVERED

This review describes the barriers to oral delivery of peptides and complex proteins, current oral delivery strategies utilized and the opportunities and challenges ahead to try and circumvent these barriers. Oral protein drugs on the market and clinical trials provide insights and approaches for advancing delivery strategies.

EXPERT OPINION

Although most current studies on oral protein delivery rely on in vitro and in vivo animal data, the safety and limitations of the approach in humans remain uncertain. The shortage of clinical data limits the development of new or alternative strategies. Therefore, designing appropriate oral delivery strategies remains a significant challenge and requires new ideas, innovative design strategies and novel model systems.

Development of Phytochemical Delivery Systems by Nano-Suspension and Nano-Emulsion Techniques

The awareness of the existence of plant bioactive compounds, namely, phytochemicals (PHYs), with health properties is progressively expanding. Therefore, their massive introduction in the normal diet and in food supplements and their use as natural therapeutics to treat several diseases are increasingly emphasized by several sectors. In particular, most PHYs possessing antifungal, antiviral, anti-inflammatory, antibacterial, antiulcer, anti-cholesterol, hypoglycemic, immunomodulatory, and antioxidant properties have been isolated from plants. Additionally, their secondary modification with new functionalities to further improve their intrinsic beneficial effects has been extensively investigated. Unfortunately, although the idea of exploiting PHYs as therapeutics is amazing, its realization is far from simple, and the possibility of employing them as efficient clinically administrable drugs is almost utopic. Most PHYs are insoluble in water, and, especially when introduced orally, they hardly manage to pass through physiological barriers and scarcely reach the site of action in therapeutic concentrations. Their degradation by enzymatic and microbial digestion, as well as their rapid metabolism and excretion, strongly limits their in vivo activity. To overcome these drawbacks, several nanotechnological approaches have been used, and many nanosized PHY-loaded delivery systems have been developed. This paper, by reporting various case studies, reviews the foremost nanosuspension- and nanoemulsion-based techniques developed for formulating the most relevant PHYs into more bioavailable nanoparticles (NPs) that are suitable or promising for clinical application, mainly by oral administration. In addition, the acute and chronic toxic effects due to exposure to NPs reported so far, the possible nanotoxicity that could result from their massive employment, and ongoing actions to improve knowledge in this field are discussed. The state of the art concerning the actual clinical application of both PHYs and the nanotechnologically engineered PHYs is also reviewed.

Interactions of Nanomaterials with Gut Microbiota and Their Applications in Cancer Therapy

Cancer treatment is a challenge by its incredible complexity. As a key driver and player of cancer, gut microbiota influences the efficacy of cancer treatment. Modalities to manipulate gut microbiota have been reported to enhance antitumor efficacy in some cases. Nanomaterials (NMs) have been comprehensively applied in cancer diagnosis, imaging, and theranostics due to their unique and excellent properties, and their effectiveness is also influenced by gut microbiota. Nanotechnology is capable of targeting and manipulating gut microbiota, which offers massive opportunities to potentiate cancer treatment. Given the complexity of gut microbiota-host interactions, understanding NMs-gut interactions and NMs-gut microbiota interactions are important for applying nanotechnologies towards manipulating gut microbiota in cancer prevention and treatment. In this review, we provide an overview of NMs-gut interactions and NMs-gut microbiota interactions and highlight the influences of gut microbiota on the diagnosis and treatment effects of NMs, further illustrating the potential of nanotechnologies in cancer therapy. Investigation of the influences of NMs on cancer from the perspective of gut microbiota will boost the prospect of nanotechnology intervention of gut microbiota for cancer therapy.

Protective effect and mechanism insight of purified Antarctic kill phospholipids against mice ulcerative colitis combined with bioinformatics

Antarctic krill oil is functional oil and has a complex phospholipids composition that poses difficulties in elucidating its effect mechanism on ulcerative colitis (UC). The mechanism of UC action was studied by bioinformatics, and the therapeutic effect of Antarctic krill phospholipids (APL) on dextran sulfate sodium (DSS)-induced colitis mice was verified. GO functional enrichment analysis uncovered an enrichment of these genes in the regulation of cell-cell adhesion, membrane region, signaling receptor activator activity, and cytokine activity. Meanwhile, the KEGG results revealed the genes were enriched in the TNF signaling pathway, pathogenic Escherichia coli infection, inflammatory bowel disease and tight junction. Animal experiments showed that APL treatment alleviated the UC symptoms and reduced inflammatory damage. Meanwhile, the expressions of the tight junction (TJ) proteins, ZO-1 and occludin, were restored, and the levels of IL-6 and TNF-α were reduced. Moreover, Firmicutes/Bacteroidetes ratio in the intestinal microbiota was regulated, and the contents of short-chain fatty acids metabolites were raised. These findings would provide an insight for the beneficial effects of APL and dietary therapy strategies for UC.

Gram-scale preparation of quercetin supramolecular nanoribbons for intestinal inflammatory diseases by oral administration

Gastrointestinal (GI) tract, which possesses the largest surface area of mucosa in the body, is easily suffered from inflammatory damages under the exposure of external stimulations. Excessive reactive oxygen species (ROS) production and continuous oxidative stress in intestines can elicit local mucosal injury, accelerate mucosal ulceration, and amplify the inflammatory response. Thereby, antioxidant therapy is a potential strategy against intestinal inflammatory diseases. Herein, we demonstrate the gram-scale preparation of quercetin supramolecular nanoribbons (SNRs) by using free quercetin molecules as the sole building block for preventing and treating intestinal inflammatory diseases. Unlike current clinical medicines, which mainly confront with poor response and severe adverse effects via bloodstream delivery, our quercetin SNRs possess an excellent antioxidant activity in the harsh environments of GI tract, a relative long retention time in GI tract, an admirable metabolism in GI tract without burdening other organs, and a specific adhesion to the inflamed intestinal epithelium via electrostatic interactions. These advantages strongly guarantee the applications of quercetin SNRs as oral medicines for intestinal inflammatory diseases. After establishing the models of intestinal inflammatory diseases caused by irradiation and drug stimulations, our quercetin SNRs exhibit the promising protective and therapeutic effects for radiation-induced acute enteritis and dextran sulfate sodium (DSS)-induced acute colitis. Because the super easy and fast preparation procedure and the nearly 100% loading capacity of quercetin SNRs, the current work provides a supramolecular nanomedicine with great clinical translation potential against intestinal inflammatory diseases.

Protective effect of sodium butyrate on intestinal barrier damage and uric acid reduction in hyperuricemia mice

PURPOSE

The goal of this study was to examine the role of sodium butyrate in preserving the intestinal mucosal barrier and reducing hyperuricemia (HUA).

METHODS

First, we established a mouse model of HUA via intraperitoneal injection of potassium oxonate together with a yeast-rich diet to detect the levels of serum uric acid (UA) and fecal short-chain fatty acids (SCFAs). Then, in vitro, different concentrations of UA and sodium butyrate (NaB) were used to treat LS174T and Caco2 cells. The effects of UA and NaB on the gut barrier were determined based on the expression levels of MUC2, ZO-1, and Occludin.Finally, C57BL/6 mice were used to model HUA, and these mice were administered 200 mg·kg^-1·d^-1 NaB by gavage to counter the HUA. The effect of NaB on HUA in the intestinal tract was elucidated by determining serum UA levels, inflammatory parameters, epithelial barrier integrity, and via histological analysis.

RESULTS

The data showed that the content of fecal SCFAs in HUA mice decreased. Additionally, in LS174T and Caco2 cells, NaB reversed the decrease of ZO-1, Occludin, and MUC2 protein expression caused by high UA levels. Furthermore, NaB decreased serum UA of HUA mice, and reversed both the decreased expression of MUC2, ZO-1, Occludin, and ABCG2 proteins and the increased level of inflammatory factors in the intestinal tissues of these mice.

CONCLUSION

The HUA mouse model showed intestinal barrier damage. NaB protected the intestinal barrier of HUA mice and reduced the serum UA level.

Combination Therapy with Indigo and Indirubin for Ulcerative Colitis via Reinforcing Intestinal Barrier Function

Indigo and indirubin, the active molecules of traditional Chinese medicine indigo naturalis, exert therapeutic activity for ulcerative colitis (UC). Indigo and indirubin are isomers and have distinctive profiles in anti-inflammation, immune regulation, intestinal microbiota regulation, oxidative stress regulation, and intestinal mucosal repair for UC treatment. Thus, exploring its combined administration's integrated advantages for UC is critical. This study is aimed at clarifying the effect and mechanisms of the combined administration of indigo and indirubin on colitis mouse models. The results showed that all the treatment groups could improve the disease symptoms, and the combined administration showed the best effect. Additionally, compared with indigo and indirubin alone, the combination group could significantly reinforce intestinal barrier function by increasing the expression of E-cadherin, occludin, ZO-1, and MUC2 and improving intestinal permeability. The treatment groups significantly improved the expression of cytokines, including TNF-α, IFN-γ, IL-12, IL-23, and IL-17A, and indirubin presented the most potent anti-inflammatory effect. Furthermore, all the treatment groups reduced the infiltration of the immune cells in intestinal lamina propria and the production of ROS/RNS. Notably, indigo exhibited a more substantial capacity to regulate natural killer (NK) cells, ILC3, neutrophils, and dendritic cells, followed by the combination group and indirubin alone. Finally, all the treatment groups modulated intestinal microbiota composition, increased the proportion of beneficial microbiota, and decreased the proportion of microbiota. Our results indicated that indigo and indirubin synergistically reinforced the intestinal barrier function, which may be associated with integrating the indirubin anti-inflammatory and intestinal microbiota regulating strength and indigo immune and ROS/RNS regulation advantage.

The gut odorant receptor and taste receptor make sense of dietary components: A focus on gut hormone secretion

Odorant receptors (ORs) and taste receptors (TRs) are expressed primarily in the nose and tongue in which they transduce electrical signals to the brain. Advances in deciphering the dietary component-sensing mechanisms in the nose and tongue prompted research on the role of gut chemosensory cells. Acting as the pivotal interface between the body and dietary cues, gut cells "smell" and "taste" dietary components and metabolites by taking advantage of chemoreceptors-ORs and TRs, to maintain physiological homeostasis. Here, we reviewed this novel field, highlighting the latest discoveries pertinent to gut ORs and TRs responding to dietary components, their impacts on gut hormone secretion, and the mechanisms involved. Recent studies indicate that gut cells sense dietary components including fatty acid, carbohydrate, and phytochemical by activating relevant ORs, thereby modulating GLP-1, PYY, CCK, and 5-HT secretion. Similarly, gut sweet, umami, and bitter receptors can regulate the gut hormone secretion and maintain homeostasis in response to dietary components. A deeper understanding of the favorable influence of dietary components on gut hormone secretion via gut ORs and TRs, coupled with the facts that gut hormones are involved in diverse physiological or pathophysiological phenomena, may ultimately lead to a promising treatment for various human diseases.

Gold nanoparticles-embedded ceria with enhanced antioxidant activities for treating inflammatory bowel disease

The excessive reactive oxygen species (ROS) is a hallmark associated with the initiation and progression of inflammatory bowel disease (IBD), which execrably form a vicious cycle of ROS and inflammation to continually promote disease progression. Here, the gold nanoparticles-embedded ceria nanoparticles (Au/CeO₂) with enhanced antioxidant activities are designed to block this cycle reaction for treating IBD by scavenging overproduced ROS. The Au/CeO₂ with core-shell and porous structure exhibits significantly higher enzymatic catalytic activities compared with commercial ceria nanoparticles, likely due to the effective exposure of catalytic sites, higher content of Ce (III) and oxygen vacancy, and accelerated reduction from Ce (IV) to Ce (III). Being coated with negatively-charged hyaluronic acid, the Au/CeO₂@HA facilitates accumulation in inflamed colon tissues via oral administration, reduces pro-inflammatory cytokines, and effectively alleviates colon injury in colitis mice. Overall, the Au/CeO₂@HA with good biocompatibility is a promising nano-therapeutic for treating IBD.

miRNA-encapsulated abiotic materials and biovectors for cutaneous and oral wound healing: Biogenesis, mechanisms, and delivery nanocarriers

MicroRNAs (miRNAs) as therapeutic agents have attracted increasing interest in the past decade owing to their significant effectiveness in treating a wide array of ailments. These polymerases II-derived noncoding RNAs act through post-transcriptional controlling of different proteins and their allied pathways. Like other areas of medicine, researchers have utilized miRNAs for managing acute and chronic wounds. The increase in the number of patients suffering from either under-healing or over-healing wound demonstrates the limited efficacy of the current wound healing strategies and dictates the demands for simpler approaches with greater efficacy. Various miRNA can be designed to induce pathway beneficial for wound healing. However, the proper design of miRNA and its delivery system for wound healing applications are still challenging due to their limited stability and intracellular delivery. Therefore, new miRNAs are required to be identified and their delivery strategy needs to be optimized. In this review, we discuss the diverse roles of miRNAs in various stages of wound healing and provide an insight on the most recent findings in the nanotechnology and biomaterials field, which might offer opportunities for the development of new strategies for this chronic condition. We also highlight the advances in biomaterials and delivery systems, emphasizing their challenges and resolutions for miRNA-based wound healing. We further review various biovectors (e.g., adenovirus and lentivirus) and abiotic materials such as organic and inorganic nanomaterials, along with dendrimers and scaffolds, as the delivery systems for miRNA-based wound healing. Finally, challenges and opportunities for translation of miRNA-based strategies into clinical applications are discussed.

Disrupted microbiota-barrier-immune interaction in phthalates-mediated barrier defect in the duodenum

As one of the most used phthalates, Di (2-ethylhexyl) phthalate (DEHP) is a widespread environmental contaminant. Extremely persistent plastic can enter the food chain of animals through the aquatic environment, affect metabolic pathways and cause damage to the digestive system. But the molecular mechanism of its toxic effects on the duodenum in birds has not been elucidated. To investigate the toxicity of phthalates in the duodenum, quails were gavaged with 250, 500, and 750 mg/kg doses of DEHP for 45 days, and water and oil control groups were retained. This study revealed that subchronic exposure to DEHP could lead to duodenal barrier defect in quail. The damage to duodenum was reflected in a reduction in V/C and tight junction proteins. Moreover, DEHP also led to a breakdown of antimicrobial defenses through the flora derangement, which acted as a biological barrier. The massive presence of Lipopolysaccharide (LPS) led to the activation of TLR4 receptors. In addition, DEHP activated oxidative stress, which synergized the inflammatory response induced by the TLR4-NFκB pathway, and further promoted duodenum damage. This study provides a base for the further effect of phthalates on the microbiota-barrier-immune interaction.

Targeting pathophysiological changes using biomaterials-based drug delivery systems: A key to managing inflammatory bowel disease

Inflammatory bowel disease (IBD) is a gastrointestinal disorder, affecting about several million people worldwide. Current treatments fail to adequately control some clinical symptoms in IBD patients, which can adversely impact the patient's quality of life. Hence, the development of new treatments for IBD is needed. Due to their unique properties such as biocompatibility and sustained release of a drug, biomaterials-based drug delivery systems can be regarded as promising candidates for IBD treatment. It is noteworthy that considering the pathophysiological changes occurred in the gastrointestinal tract of IBD patients, especially changes in pH, surface charge, the concentration of reactive oxygen species, and the expression of some biomolecules at the inflamed colon, can help in the rational design of biomaterials-based drug delivery systems for efficient management of IBD. Here, we discuss about targeting these pathophysiological changes using biomaterials-based drug delivery systems, which can provide important clues to establish a strategic roadmap for future studies.

Toxicity Analysis of Mesoporous Polydopamine on Intestinal Tissue and Microflora

As a promising therapy, photothermal therapy (PTT) converts near-infrared (NIR) light into heat through efficient photothermal agents (PTAs), causing a rapid increase in local temperature. Considering the importance of PTAs in the clinical application of PTT, the safety of PTAs should be carefully evaluated before their widespread use. As a promising PTA, mesoporous polydopamine (MPDA) was studied for its clinical applications for tumor photothermal therapy and drug delivery. Given the important role that intestinal microflora plays in health, the impacts of MPDA on the intestine and on intestinal microflora were systematically evaluated in this study. Through biological and animal experiments, it was found that MPDA exhibited excellent biocompatibility, in vitro and in vivo. Moreover, 16S rRNA analysis demonstrated that there was no obvious difference in the composition and classification of intestinal microflora between different drug delivery groups and the control group. The results provided new evidence that MPDA was safe to use in large doses via different drug delivery means, and this lays the foundation for further clinical applications.

Oral Nanomedicines for siRNA Delivery to Treat Inflammatory Bowel Disease

RNA interference (RNAi) therapies have significant potential for the treatment of inflammatory bowel diseases (IBD). Although administering small interfering RNA (siRNA) via an oral route is desirable, various hurdles including physicochemical, mucus, and cellular uptake barriers of the gastrointestinal tract (GIT) impede both the delivery of siRNA to the target site and the action of siRNA drugs at the target site. In this review, we first discuss various physicochemical and biological barriers in the GI tract. Furthermore, we present recent strategies and the progress of oral siRNA delivery strategies to treat IBD. Finally, we consider the challenges faced in the use of these strategies and future directions of oral siRNA delivery strategies.

Changes of physico-chemical properties of nano-biomaterials by digestion fluids affect the physiological properties of epithelial intestinal cells and barrier models

Background

The widespread use of nano-biomaterials (NBMs) has increased the chance of human exposure. Although ingestion is one of the major routes of exposure to NBMs, it is not thoroughly studied to date. NBMs are expected to be dramatically modified following the transit into the oral-gastric-intestinal (OGI) tract. How these transformations affect their interaction with intestinal cells is still poorly understood. NBMs of different chemical nature—lipid-surfactant nanoparticles (LSNPs), carbon nanoparticles (CNPs), surface modified Fe₃O₄ nanoparticles (FNPs) and hydroxyapatite nanoparticles (HNPs)—were treated in a simulated human digestive system (SHDS) and then characterised. The biological effects of SHDS-treated and untreated NBMs were evaluated on primary (HCoEpiC) and immortalised (Caco-2, HCT116) epithelial intestinal cells and on an intestinal barrier model.

Results

The application of the in vitro SDHS modified the biocompatibility of NBMs on gastrointestinal cells. The differences between SHDS-treated and untreated NBMs could be attributed to the irreversible modification of the NBMs in the SHDS. Aggregation was detected for all NBMs regardless of their chemical nature, while pH- or enzyme-mediated partial degradation was detected for hydroxyapatite or polymer-coated iron oxide nanoparticles and lipid nanoparticles, respectively. The formation of a bio-corona, which contains proteases, was also demonstrated on all the analysed NBMs. In viability assays, undifferentiated primary cells were more sensitive than immortalised cells to digested NBMs, but neither pristine nor treated NBMs affected the intestinal barrier viability and permeability. SHDS-treated NBMs up-regulated the tight junction genes (claudin 3 and 5, occludin, zonula occludens 1) in intestinal barrier, with different patterns between each NBM, and increase the expression of both pro- and anti-inflammatory cytokines (IL-1β, TNF-α, IL-22, IL-10). Notably, none of these NBMs showed any significant genotoxic effect.

Conclusions

Overall, the results add a piece of evidence on the importance of applying validated in vitro SHDS models for the assessment of NBM intestinal toxicity/biocompatibility. We propose the association of chemical and microscopic characterization, SHDS and in vitro tests on both immortalised and primary cells as a robust screening pipeline useful to monitor the changes in the physico-chemical properties of ingested NBMs and their effects on intestinal cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12989-022-00491-w.

Extracellular Vesicles—Oral Therapeutics of the Future

Considered an artifact just after discovery, the possibility of oral delivery of extracellular vesicles (EVs) and their functional cargos has recently gained much research attention. EVs from various sources, including edible plants, milk, bacteria and mammalian cells, have emerged as a platform for miRNA and drug delivery that seem to induce the expected immune effects locally and in distant tissues after oral administration. Such a possibility greatly expands the clinical applicability of EVs. The present review summarizes research findings that either support or deny the biological/therapeutical activity of orally administered EVs and their role in cross-species and cross-kingdom signaling.

Smart pH-responsive nanomedicines for disease therapy

Background

Currently nanomedicines are the focus of attention from researchers and clinicians because of the successes of lipid-nanoparticles-based COVID-19 vaccines. Nanoparticles improve existing treatments by providing a number of advantages including protection of cargo molecules from external stresses, delivery of drugs to target tissues, and sustained drug release. To prevent premature release-related side effects, stable drug loading in nanoformulations is required, but the increased stability of the formulation could also lead to a poor drug-release profile at the target sites. Thus, researchers have exploited differences in a range of properties (e.g., enzyme levels, pH, levels of reduced glutathione, and reactive oxygen species) between non-target and target sites for site-specific release of drugs. Among these environmental stimuli, pH gradients have been widely used to design novel, responsive nanoparticles.

Area covered

In this review, we assess drug delivery based on pH-responsive nanoparticles at the levels of tissues (tumor microenvironment, pH ~ 6.5) and of intracellular compartments (endosome and lysosome, pH 4.5-6.5). Upon exposure to these pH stimuli, pH-responsive nanoparticles respond with physicochemical changes to their material structure and surface characteristics. These changes include swelling, dissociation, or surface charge switching, in a manner that favors drug release at the target site (the tumor microenvironment region and the cytosol followed by endosomal escape) rather than the surrounding tissues.

Expert opinion

Lastly, we consider the challenges involved in the development of pH-responsive nanomedicines.