Hollow CeO2 with ROS-Scavenging Activity to Alleviate Colitis in Mice

Construction of CeO2/Ti3C2Tx heterojunction with antibacterial and antioxidant capabilities for diabetic wound healing

Diabetic wounds are highly prone to persistent pathogenic infections due to the complex nature of their microenvironment, which significantly hinders the healing process under hyperglycemic conditions. In this study, we developed a bio-heterojunction enzyme system consisting of hollow CeO2/Ti3C2Tx MXene quantum dots (CeO2@MQD) integrated with glucose oxidase (GOx-CeO2@MQD). The GOx-CeO2@MQD system exhibits multifunctional enzymatic activities, including peroxidase (POD) and catalase (CAT)-like activity, resulting in the production of •OH and O2, alongside the consumption of glucose and glutathione (GSH). The incorporation of GOx effectively mitigates the hyperglycemic microenvironment by catalyzing glucose, leading to a significant increase in H2O2 production, which is subsequently converted into bactericidal •OH through POD activity. Furthermore, H2O2 can be catalyzed into H2O and O2 via the CAT pathway, thereby alleviating inflammation caused by the excessive accumulation of reactive oxygen species. In vitro antibacterial assays demonstrated that the GOx-CeO2@MQD system achieved remarkable bactericidal efficiencies of 99.99% against E. coli and S. aureus at concentrations of 12.5 ppm and 2.0 ppm, respectively. In vivo experiments further revealed that GOx-CeO2@MQD significantly promoted angiogenesis, accelerated wound epithelialization, and induced a strong anti-inflammatory response, thus facilitating the regeneration of infected diabetic skin. This study proposes a novel approach for diabetic wound treatment by harnessing the synergistic effects of multiple enzyme-like activities.

Nucleic Acid-Functionalized Gold Nanorods Modulate Inflammation and Dysregulated Intestinal Barriers for Treatment of Ulcerative Colitis

Traditional oral treatments for ulcerative colitis (UC) face marked limitations including their single therapeutic effect, potential off-target interactions, and toxic side effects. In this study, we present nucleic acid-functionalized gold nanorods (NAF AuNRs), a biocompatible nanomaterial designed for the oral treatment of dextran sulfate sodium (DSS)-induced colitis. The NAF AuNRs alleviate immune responses by inhibiting pro-inflammatory macrophages and enhancing the expression of barrier proteins in intestinal epithelial cells. Due to the negatively charged nucleic acid shell, NAF AuNRs preferentially target anionic, inflamed colon tissues upon oral administration, reducing pro-inflammatory cytokine levels and promoting the recovery of intestinal barrier in DSS-induced colitis mice. Collectively, these findings suggest that NAF AuNRs represent an innovative and promising therapeutic approach for UC management, offering novel insights into the application of nucleic acid-functionalized nanomaterials.

Gelatin methacryloyl-phenylboronic acid/Hydroxyadamantane self-healing microgels for the periodontitis treatment by promoting alveolar bone regeneration

Periodontitis is a chronic inflammatory condition mainly caused by the interaction between the host immune system and periodontal tissue pathogens, and may lead to consequences, such as alveolar bone defects and tooth loss. Incomplete bacterial removal, persistent inflammation and high reactive oxygen species (ROS) environment are the main challenges for periodontal tissue repair and alveolar bone regeneration. In this study, an injectable composite microgel (Gelatin methacryloyl-Phenylboronic acid/Hydroxyadamantane, GPH) loaded with antimicrobial peptide (AMP) and cerium dioxide (CeO2) microspheres was developed to achieve a synergistic function of bacteriostasis, immunomodulation, and ROS removal. In vitro studies had shown that the composite microgel had an inhibitory rate of >99 % against E. coli, S. aureus and P. gingivalis and scavenged DPPH with a rate of 87.1 % ± 2.0 %, exhibiting excellent antibacterial and antioxidant properties. In addition, it was able to promote macrophage phenotypic shift from M1-type to M2-type and reduce ROS levels, and also had excellent biocompatibility. Mechanistically, the composite microgel was subjected to transcriptome sequencing analysis of gene expression levels and signaling pathways in BMSC cells, and the results showed that the microgel played an important role in regulating the PI3K-Akt and chemokine signaling pathways, which in turn inhibited the expression of inflammatory factors. In vivo the effect of composite microgel on periodontal tissue repair and alveolar bone regeneration was verified by infected alveolar bone defect model. The results showed that after 4 weeks of using the composite microgel, the bone volume per unit of tissue volume of the alveolar bone, the thickness of bone trabeculae, and the bone mineral density reached 25.94 % ± 0.03 %, 0.14 mm ± 0.01 mm, and 0.442 g/cm3 ± 0.003 g/cm3, respectively, while those of the control group were 22.3 % ± 0.29 %, 0.07 mm ± 0.02 mm, and 0.236 g/cm3 ± 0.059 g/cm3, respectively, and the use of the composite microgel resulted in significantly better repair results than the control group. In addition, pro-inflammatory factors were significantly suppressed and inflammation levels were significantly reduced. Overall, this composite microgel showed great potential in reducing inflammation levels and promoting alveolar bone regeneration, providing an innovative approach to the treatment of periodontitis.

Hollow cerium nanoparticles synthesized by one-step method for multienzyme activity to reduce colitis in mice

BACKGROUND

Inflammatory bowel disease (IBD) is a common chronic intestinal inflammatory disease. High oxidative stress is a treatment target for IBD. Cerium oxide (CeO2) nanomaterials as nanozymes with antioxidant activity are potential drugs for the treatment of colitis.

AIM

To synthesize hollow cerium (H-CeO2) nanoparticles by one-step method and to validate the therapeutic efficacy of H-CeO2 in IBD.

METHODS

H-CeO2 was synthesized by one-step method and examined its characterization and nanoenzymatic activity. Subsequently, we constructed dextran sulfate sodium (DSS)-induced colitis in mice to observe the effects of H-CeO2 on colonic inflammation. The effects of H-CeO2 on colon inflammation and reactive oxygen species (ROS) levels in IBD mice were detected by hematoxylin and eosin staining and dichlorofluorescein diacetate staining, respectively. Finally, the biological safety of H-CeO2 on mice was evaluated by hematoxylin and eosin staining, blood routine, and blood biochemistry.

RESULTS

H-CeO2 nanoparticles prepared by the one-step method were uniform, monodisperse and hollow. H-CeO2 had a good ability to scavenge ROS, ∙OH and ∙OOH. H-CeO2 reduced DSS-induced decreases in body weight and colon length, colonic epithelial damage, inflammatory infiltration, and ROS accumulation. H-CeO2 administration reduced the disease activity index of DSS-induced animals from about 8 to 5. H-CeO2 had no significant effect on body weight, total platelet count, hemoglobin, white blood cell, and red blood cell counts in healthy mice. No significant damage to major organs was observed in healthy mice following H-CeO2 administration.

CONCLUSION

The one-step synthesis of H-CeO2 nanomaterials had good antioxidant activity, biosafety, and inhibited development of DSS-induced IBD in mice by scavenging ROS.

Ligand-to-Metal Ratio Governs Radical-Scavenging Ability of Malate-Stabilised Ceria Nanoparticles

Cerium dioxide sols stabilised with L-malic acid were shown to exhibit significant antioxidant activity towards alkyl peroxyl radicals in the range of ligand:CeO2 molar ratios of 0.2-1 (0.2:1, 0.4:1, 0.5:1, 0.6:1, 0.8:1 and 1:1). The antioxidant activity of cerium dioxide nanoparticles greatly depended on L-malic acid content and increased by 8 times when the ligand:CeO2 molar ratio increased from 0.2:1 to 0.4:1. An estimate of the ligand:CeO2 molar ratio required to ensure complete surface coverage of CeO2 nanoparticles with malate anions resulted in a value of 0.2. Aggregation degree of CeO2 nanoparticles depends on the ligand:CeO2 molar ratio. In the range of ligand:CeO2 molar ratios 0.2-0.4, the size of aggregates decreased by an order of magnitude. The antioxidant capacity of 1 mM malate-stabilised cerium dioxide (0.2:1) relative to sodium ascorbate was 0.012 ± 0.001 mM. The antioxidant activity of cerium dioxide stabilised with L-malic acid at a ligand:CeO2 molar ratio of 0.2:1 was 80 times less than the antioxidant activity of sodium ascorbate. Cerium dioxide nanoparticles stabilised with L-malic acid did not demonstrate a cytotoxic effect against human mesenchymal stem cells, in a wide range of concentrations (10-3-10-5 M), and their proliferation was stimulated after 72 h of cultivation. The results obtained show new possibilities for the design of biocompatible ceria-based nanomaterials with tunable pro- and antioxidant properties; these materials can further be assessed in view of their potential for treating oxidative stress-related disorders.

Nostoxanthin Biosynthesis by Sphingomonas Species (COS14-R2): Isolation, Identification, and Optimization of Culture Conditions

Nostoxanthin, a yellow pigment, belongs to the xanthophyll group of carotenoids found in various species of bacteria and cyanobacteria. Several species of Sphingomonas can produce appropriate carotenoids for survive in various environments. This comprise nostoxanthin, a significant carotenoid. The study isolated the Sphingomonas species strain COS14-R2 from the Cosmos bipinnatus and identified it through the whole-genome sequence. The strain consists of a circular chromosome with a length of 3,677,457 base pairs.s ecThe genome consists of three carotenoid biosynthesis genes, specifically crtB (phytoene synthase), crtI (phytoene desaturase), and crtY (Lycopene beta-cyclase), which are involved in the synthesis of nostoxanthin. The strain has a circular, undulated colony morphology with a deep yellow color. It demonstrates optimal growth in liquid media at 25 to 35 °C and exhibits a high tolerance for pH levels between 5 and 11 and requires adequate quantities of carbon and nitrogen. We observed the highest concentration of nostoxanthin was recorded at 35 °C, pH of 7.5, glucose concentration of 40 g L-1, and a yeast extract concentration of 5 g L-1 during dark incubation. The fed-batch fermentation process produced nostoxanthin at a concentration of 217.22 ± 9.60 mg L-1, with a selectivity of 72.32% and a productivity of 2.59 g/L/h. The dry biomass extract was purified using column chromatography. The LC-MS/MS analysis of the purified fraction indicated that the molecular weight of nostoxanthin is 600.5098 m/z. The DPPH assay result of 75.5 ± 0.33% indicates nostoxanthin is highly effective in scavenging free radicals.

Multifunctional human serum albumin-crosslinked and self-assembling nanoparticles for therapy of periodontitis by anti-oxidation, anti-inflammation and osteogenesis

Periodontitis is a chronic inflammatory disease that can result in the irreversible loss of tooth-supporting tissues and elevate the likelihood and intensity of systemic diseases. The presence of reactive oxygen species (ROS) and associated related oxidative stress is intricately linked to the progression and severity of periodontal inflammation. Targeted removal of local ROS may serve to attenuate inflammation, improve the unfavorable periodontal microenvironment and potentially reverse ensuing pathological cascades. These ROS scavenging nanoparticles, which possess additional characteristics such as anti-inflammation and osteogenic differentiation, are highly sought after for the treatment of periodontitis. In this study, negative charged human serum albumin-crosslinked manganese-doped self-assembling Prussian blue nanoparticles (HSA-MDSPB NPs) were fabricated. These nanoparticles demonstrate the ability to scavenge multiple ROS including superoxide anion, free hydroxyl radicals, singlet oxygen and hydrogen peroxide. Additionally, HSA-MDSPB NPs exhibit the capacity to alleviate inflammation in gingiva and alveolar bone both in vitro and in vivo. Furthermore, HSA-MDSPB NPs have been shown to play a role in promoting the polarization of macrophages from the M1 to M2 phenotype, resulting in reduced production of pro-inflammatory cytokines. More attractively, HSA-MDSPB NPs have been demonstrated to enhance cellular osteogenic differentiation. These properties of HSA-MDSPB NPs contribute to decreased inflammation, extracellular matrix degradation and bone loss in periodontal tissue. In conclusion, the multifunctional nature of HSA-MDSPB NPs provides a promising therapeutic approach for the treatment of periodontitis.

Treatment of Rheumatoid Arthritis Based on the Inherent Bioactivity of Black Phosphorus Nanosheets

Rheumatoid arthritis (RA) is an autoimmune disease that affects the living quality of patients, especially the elderly population. RA-related morbidity and mortality increase significantly with age, while current clinical drugs for RA are far from satisfactory and may have serious side effects. Therefore, the development of new drugs with higher biosafety and efficacy is demanding. Black phosphorus nanosheets (BPNSs) have been widely studied because of their excellent biocompatibility. Here, we focus on the inherent bioactivity of BPNSs, report the potential of BPNSs as a therapeutic drug for RA and elucidate the underlying therapeutic mechanism. We find that BPNSs inhibit autophagy at an early stage via the AMPK-mTOR pathway, switch the energy metabolic pathway to oxidative phosphorylation, increase intracellular ATP levels, suppress apoptosis, reduce inflammation and oxidative stress, and down-regulate senescence-associated secretory phenotype (SASP)-related genes in rheumatoid arthritis synovial fibroblasts (RA-SFs). Further, BPNSs induce the apoptosis of macrophages and promote their transition from the M1 to the M2 phenotype by regulating related cytokines. Significantly, the administration of BPNSs can alleviate key pathological features of RA in mice, revealing great therapeutic potential. This study provides a novel option for treating RA, with BPNSs emerging as a promising therapeutic candidate.

Epigallocatechin-3-gallate derived polymer coated Prussian blue for synergistic ROS elimination and antibacterial therapy

Reactive oxygen species (ROS) play a vital role in wound healing process by fighting against invaded bacteria. However, excess ROS at the wound sites lead to oxidative stress that can trigger deleterious effects, causing cell death, tissue damage and chronic inflammation. Therefore, we fabricated a core-shell structured nanomedicine with antibacterial and antioxidant properties via a facile and green strategy. Specifically, Prussian blue (PB) nanozyme was fabricated and followed by coating a layer of epigallocatechin-3-gallate (EGCG)-derived polymer via polyphenolic condensation reaction and self-assembly process, resulting in PB@EGCG. The introduction of PB core endowed EGCG-based polyphenol nanoparticles with excellent NIR-triggered photothermal properties. Besides, owing to multiple enzyme-mimic activity of PB and potent antioxidant capacity of EGCG-derived polymer, PB@EGCG exhibited a remarkable ROS-scavenging ability, mitigated intracellular ROS level and protected cells from oxidative damage. Under NIR irradiation (808 nm, 1.5 W/cm2), PB@EGCG (50 µg/mL) exerted synergistic EGCG-derived polymer-photothermal antibacterial activity against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). In vivo therapeutic effect was evaluated using a S. aureus-infected rat model indicated PB@EGCG with a prominent bactericidal ability could modulate the inflammatory microenvironment and accelerate wound healing. Overall, this dual-functional nanomedicine provides a promising strategy for efficient antibacterial therapy.

Combined ROS Responsive Polydopamine-Coated Berberine Nanoparticles Effective Against Ulcerative Colitis in Mouse Model

Introduction

Enhancing the efficacy of berberine (BBR) in the treatment of ulcerative colitis (UC) through the development of dopamine-coated berberine nanoparticles (PDA@BBR NPs) with ROS-responsive and adhesive properties.

Methods

Berberine nanoparticles (BBR NPs) were synthesized using the nonsolvent precipitation method, and their surfaces were coated with polydopamine (PDA) through oxidative polymerization. The PDA@BBR NPs were characterized by transmission electron microscopy (TEM), size analysis, and zeta potential analysis. Drug loading and encapsulation efficiency were analyzed using fluorescence spectroscopy. The responsiveness of these nanoparticles to reactive oxygen species (ROS) was assessed in vitro, while their adhesive properties and therapeutic efficacy on UC were evaluated in vivo.

Results

Physicochemical property studies showed that PDA coated BBR NPs nanoparticles have good dispersion and stability. In vitro results showed that PDA@BBR NPs could prolong the retention time of the drug at the colonic site and could realize the gradual drug release under ROS environment. In addition, animal studies showed that PDA@BBR NPs exhibited significant anti-inflammatory effects on DSS-induced colitis and effectively reduced intestinal mucosal damage.

Conclusion

PDA@BBR NPs are ROS-responsive nanoparticles that adhere well and have a high drug loading capacity. They have shown therapeutic effects in mice with UC, indicating that this formulation may be a promising treatment option.

The progression of inorganic nanoparticles and natural products for inflammatory bowel disease

There is a growing body of evidence indicating a close association between inflammatory bowel disease (IBD) and disrupted intestinal homeostasis. Excessive production of reactive oxygen species (ROS) and reactive nitrogen species (RNS), along with an increase in M1 proinflammatory macrophage infiltration during the activation of intestinal inflammation, plays a pivotal role in disrupting intestinal homeostasis in IBD. The overabundance of ROS/RNS can cause intestinal tissue damage and the disruption of crucial gut proteins, which ultimately compromises the integrity of the intestinal barrier. The proliferation of M1 macrophages contributes to an exaggerated immune response, further compromising the intestinal immune barrier. Currently, intestinal nanomaterials have gained widespread attention in the context of IBD due to their notable characteristics, including the ability to specifically target regions of interest, clear excess ROS/RNS, and mimic biological enzymes. In this review, we initially elucidated the gut microenvironment in IBD. Subsequently, we delineate therapeutic strategies involving two distinct types of nanomedicine, namely inorganic nanoparticles and natural product nanomaterials. Finally, we present a comprehensive overview of the promising prospects associated with the application of nanomedicine in future clinical settings for the treatment of IBD (graphic abstract). Different classes of nanomedicine are used to treat IBD. This review primarily elucidates the current etiology of inflammatory bowel disease and explores two prominent nanomaterial-based therapeutic approaches. First, it aims to eliminate excessive reactive oxygen species and reactive nitrogen species. Second, they focus on modulating the polarization of inflammatory macrophages and reducing the proportion of pro-inflammatory macrophages. Additionally, this article delves into the treatment of inflammatory bowel disease using inorganic metal nanomaterials and natural product nanomaterials.

Restoration of dysregulated intestinal barrier and inflammatory regulation through synergistically ameliorating hypoxia and scavenging reactive oxygen species using ceria nanozymes in ulcerative colitis

BACKGROUND

Reactive oxygen species (ROS) overproduction and excessive hypoxia play pivotal roles in the initiation and progression of ulcerative colitis (UC). Synergistic ROS scavenging and generating O₂ could be a promising strategy for UC treatment.

METHODS

Ceria nanozymes (PEG-CNPs) are fabricated using a modified reverse micelle method. We investigate hypoxia attenuating and ROS scavenging of PEG-CNPs in intestinal epithelial cells and RAW 264.7 macrophages and their effects on pro-inflammatory macrophages activation. Subsequently, we investigate the biodistribution, pharmacokinetic properties and long-term toxicity of PEG-CNPs in mice. PEG-CNPs are administered intravenously to mice with 2,4,6-trinitrobenzenesulfonic acid-induced colitis to test their colonic tissue targeting and assess their anti-inflammatory activity and mucosal healing properties in UC.

RESULTS

PEG-CNPs exhibit multi-enzymatic activity that can scavenge ROS and generate O₂, promote intestinal epithelial cell healing and inhibit pro-inflammatory macrophage activation, and have good biocompatibility. After intravenous administration of PEG-CNPs to colitis mice, they can enrich at the site of colonic inflammation, and reduce hypoxia-induced factor-1α expression in intestinal epithelial cells by scavenging ROS to generate O₂, thus further promoting disrupted intestinal mucosal barrier restoration. Meanwhile, PEG-CNPs can effectively scavenge ROS in impaired colon tissues and relieve colonic macrophage hypoxia to suppress the pro-inflammatory macrophages activation, thereby preventing UC occurrence and development.

CONCLUSION

This study has provided a paradigm to utilize metallic nanozymes, and suggests that further materials engineering investigations could yield a facile method based on the pathological characteristics of UC for clinically managing UC.

Nanoparticles of Cerium-Doped Zeolitic Imidazolate Framework-8 Promote Soft Tissue Integration by Reprogramming the Metabolic Pathways of Macrophages

Soft tissue integration around the abutment of implants is the basis of long-term retention of implants. Macrophages are an important component involved in the repair of soft tissue due to their crucial role in improving the biological structure of connective tissues by regulating the fiber synthesis, adhesion, and contraction of gingival fibroblasts. Recent studies have illustrated that cerium-doped zeolitic imidazolate framework-8 (Ce@ZIF-8) nanoparticles (NPs) can attenuate periodontitis via both antibacterial and anti-inflammatory effects. However, the effect of Ce@ZIF-8 NPs on soft tissue integration around the abutment is unknown. Herein, we first prepared Ce@ZIF-8 NPs by a one-pot synthesis. Then, we probed the regulatory effect of Ce@ZIF-8 NPs on macrophage polarization, and further experiments were performed to study the changes of fiber synthesis as well as adhesion and contraction of fibroblasts in the M2 macrophage environment stimulated by Ce@ZIF-8 NPs. Strikingly, Ce@ZIF-8 NPs can be internalized by M1 macrophages through macropinocytosis and caveolae-mediated endocytosis in addition to phagocytosis. By catalyzing hydrogen peroxide to produce oxygen, the mitochondrial function was remedied, while hypoxia inducible factor-1α was restrained. Then, macrophages were shifted from the M1 to M2 phenotype via this metabolic reprogramming pathway, provoking soft tissue integration. These results provide innovative insights into facilitating soft tissue integration around implants.

Effects of microplastic and engineered nanomaterials on inflammatory bowel disease: A review

Many microplastics and engineered nanomaterials (ENMs) exist in the daily environment. The intestinal impact of these exogenous fine particles on inflammatory bowel disease (IBD) people may be unpredictable. In this paper, we reviewed the recent progress in the effect of microplastics and ENMs on IBD individuals. We also compared and summarized the various roles of microplastics and ENMs in healthy and IBD bodies, including factors such as particle size, particle properties, intestinal microenvironment, interaction with the intestinal barrier, and molecular mechanism. Our literature review showed that microplastics could be accomplices in the development of IBD and could cause severe intestinal inflammation. Moreover, ENMs could elicit diverse exposure outcomes in healthy and IBD bodies. Silicon dioxide nanoparticles (SiO₂ NPs), titanium dioxide nanoparticles (TiO₂ NPs), and graphene oxide (GO) displayed slight to adverse effects that turned into apparent adverse effects, while zinc oxide nanoparticles (ZnO NPs) and silver nanoparticles (Ag NPs) showed a toxic effect that became therapeutic. A deeper understanding of the impact of microplastics and ENMs on the high-risk group was needed, and we proposed several insights into the research priorities and directions.

Polydopamine-cladded montmorillonite micro-sheets as therapeutic platform repair the gut mucosal barrier of murine colitis through inhibiting oxidative stress

Montmorillonite (MMT), a layered aluminosilicate, has a mucosal nutrient effect and restores the gut barriers integrity. However, orally administrating MMT is not effective to combat the reactive oxygen species (ROS) and alleviate the acute inflammatory relapse for colitis patients. Herein, polydopamine-doped montmorillonite micro-sheets (PDA/MMT) have been developed as a therapeutic platform for colitis treatment. SEM and EDS analysis showed that dopamine monomer (DA) was easily polymerized in alkaline condition and polydopamine (PDA) was uniformly cladded on the surface of MMT micro-sheets. The depositing amount of PDA was reaching to 2.06 ​± ​0.08%. Moreover, in vitro fluorescence probes experiments showed that PDA/MMT presented the broad spectra of scavenging various ROS sources including •OH, •O^2-, and H₂O₂. Meanwhile, the intracellular ROS of Rosup/H₂O₂ treated Caco-2 ​cell was also effectively scavenged by PDA/MMT, which resulted in the obvious improvement of the cell viability under oxidative stress. Moreover, most of orally administrated PDA/MMT was transited to the gut and form a protective film on the diseased colon. PDA/MMT exhibited the obvious therapeutic effect on DSS-induced ulcerative colitis mouse. Importantly, the gut mucosa of colitis mouse was well restored after PDA/MMT treatment. Moreover, the colonic inflammation was significantly alleviated and the goblet cells were obliviously recovered. The therapeutic mechanism of PDA/MMT was highly associated with inhibiting oxidative stress. Collectively, PDA/MMT micro-sheets as a therapeutic platform may provide a promising therapeutic strategy for UC treatment.

Orally administration of cerium oxide nanozyme for computed tomography imaging and anti-inflammatory/anti-fibrotic therapy of inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic nonspecific disease with unknown etiology. Currently, the anti-inflammatory therapeutic approaches have achieved a certain extent of effects in terms of inflammation alleviation. Still, the final pathological outcome of intestinal fibrosis has not been effectively improved yet.

RESULTS

In this study, dextran-coated cerium oxide (D-CeO₂) nanozyme with superoxide dismutase (SOD) and catalase (CAT) activities was synthesized by chemical precipitation. Our results showed that D-CeO₂ could efficiently scavenge reactive oxide species (ROS) as well as downregulate the pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, and iNOS) to protect cells from H₂O₂-induced oxidative damage. Moreover, D-CeO₂ could suppress the expression of fibrosis-related gene levels, such as α-SMA, and Collagen 1/3, demonstrating the anti-fibrotic effect. In both TBNS- and DSS-induced colitis models, oral administration of D-CeO₂ in chitosan/alginate hydrogel alleviated intestinal inflammation, reduced colonic damage by scavenging ROS, and decreased inflammatory factor levels. Notably, our findings also suggested that D-CeO₂ reduced fibrosis-related cytokine levels, predicting a contribution to alleviating colonic fibrosis. Meanwhile, D-CeO₂ could also be employed as a CT contrast agent for noninvasive gastrointestinal tract (GIT) imaging.

CONCLUSION

We introduced cerium oxide nanozyme as a novel therapeutic approach with computed tomography (CT)-guided anti-inflammatory and anti-fibrotic therapy for the management of IBD. Collectively, without appreciable systemic toxicity, D-CeO₂ held the promise of integrated applications for diagnosis and therapy, pioneering the exploration of nanozymes with ROS scavenging capacity in the anti-fibrotic treatment of IBD.

Oral Administration of Therapeutic Enzyme Capsule for the Management of Inflammatory Bowel Disease

BACKGROUND

Oral administration of proteins/peptides is challenging in clinical application due to their instability and susceptibility in the gastrointestinal tract.

MATERIALS AND METHODS

The in situ polymerization on the surface of enzymes was used to encapsulate antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)) in polymeric shells, and the reactive oxygen species (ROS) scavenging ability was monitored based on DCFH-DA probe using flow cytometry and confocal laser scanning microscopy. The mRNA expression level of pro-inflammatory factors was assessed by real-time qPCR, using lipopolysaccharide-induced RAW264.7 cells as a model. Finally, the enzyme capsules were orally administered for the treatment of inflammatory bowel disease using dextran sodium sulfate (DSS)-induced colitis mice as a model, based on the evaluation of the disease-associated index, ROS level and pro-inflammatory cytokines' expression.

RESULTS

The enzyme capsules could effectively scavenge the intracellular reactive oxygen species (ROS) through the cascade catalysis of SOD and CAT, and thus protect the cells from ROS-induced oxidative damage. Meanwhile, the enzyme capsules could inhibit the secretion of pro-inflammatory cytokines from macrophages, thereby achieving favorable anti-inflammation effect. Oral administration of enzyme capsules could facilitate the accumulation of enzymes in the inflamed colon tissues of DSS-induced colitis mice. Moreover, the oral delivery of enzyme capsules could effectively alleviate the symptoms associated with colitis, attributing to the excellent ROS scavenging ability and the inhibition of pro-inflammatory cytokines' level.

CONCLUSION

In summary, our findings provided a promising approach to construct enzyme-based nano-formulations with favorable therapeutic efficacy and biocompatibility, exhibiting great potential in the treatment of gastrointestinal diseases in an oral administration manner.