Prediction of apparent total tract digestion of crude protein in adult dogs.

To predict the apparent total tract digestibility (ATTD) of crude protein (CP) in dogs we developed an in vitro system using an in vitro digestion method and a statistical analysis. The experimental diets used chicken meat powder as the protein source, with CP levels of 20% (22.01%, analyzed CP value as dry-based), 30% (31.35%, analyzed CP value as dry-based), and 40% (41.34%, analyzed CP value as dry-based). To simulate in vivo digestive processes a static in vitro digestion was performed in two steps; stomach and small intestine. To analyze ATTD the total fecal samples were collected in eight neutered beagle dogs during the experimental period. CP digestibility was calculated by measuring CP levels in dog food, in vitro undigested fraction, and dog feces. In result, CP digestibility at both in vivo and in vitro was increased with increasing dietary CP levels. To estimate in vivo digestibility the co-relation of in vivo ATTD and in vitro digestibility was investigated statistically and a regression equation was developed to predict the CP ATTD (% = 2.5405 × in vitro CP digestibility (%) + 151.8). The regression equation was evaluated its feasibility by using a commercial diet. The predicted CP digestibility which was calculated by the regression equation showed high index of similarity (100.16%) with that of in vivo in dogs. With that, it would be a feasible non-animal method to predict in vivo CP digestibility by using in vitro digestion method and the proposed linear regression equation in adult dogs.

Research Note: Welfare and stress responses of broiler chickens raised in conventional and animal welfare-certified broiler farms.

The present study was conducted to assess the animal welfare status of broiler chickens raised in conventional and welfare-certified farms. One conventional farm (30,000 birds/house, 1,488 m2/house, 2 houses) and one animal welfare-certified farm (32,000 birds/house, 1,920 m2/house, 2 houses) were selected to measure productivity, stress responses, and animal welfare indicators in 3 broiler flocks (2 farms/season, n = 6 flocks/farm type) during summer, autumn, and spring. Upon farm visits, body weight, uniformity, and animal welfare indicators (i.e., fecal and feather corticosterone, footpad dermatitis, hock burn, feather dirtiness, and gait score) were measured at 26 d posthatch. Also, moisture, nitrogen, and pH of litter, light intensity, ammonia concentration, and body surface temperature of head, chest, and legs were measured. There was no difference in body weight and uniformity between farm types. Fecal corticosterone concentrations were higher (P = 0.021) in welfare-certified vs. conventional farm, but no significant difference was found in feather corticosterone. Welfare-certified vs. conventional farm had lower percentages of hock burn (P = 0.018), feather dirtiness scores (P = 0.009), and gait score (P = 0.040), and there was no difference in footpad dermatitis. Nitrogen content in litter samples tended to be higher in conventional vs. welfare-certified farms (P = 0.094), and there was no difference in moisture and pH between farm types. Ammonia concentration within the broiler houses was not different between 2 farms. However, animal welfare farm was found to be brighter than conventional farm (P < 0.001). The body surface temperature of head, chest, and legs was not different between farm types. In conclusion, the welfare-certified farm had higher welfare measures, including lower hock burn, feather dirtiness, and gait score, confirming an overall improvement in welfare indicators. However, the observation on the elevated feather corticosterone noted in welfare vs. conventionally raised chickens warrants further studies.

Immunogenic Extracellular Vesicles Derived from Endoplasmic Reticulum-Stressed Tumor Cells: Implications as the Therapeutic Cancer Vaccine.

Tumor-derived extracellular vesicles (TDEs) have potential for therapeutic cancer vaccine applications since they innately possess tumor-associated antigens, mediate antigen presentation, and can incorporate immune adjuvants for enhanced vaccine efficacy. However, the original TDEs also contain immune-suppressive proteins. To address this, we proposed a simple yet powerful preconditioning method to improve the overall immunogenicity of the TDEs. This approach involved inducing endoplasmic reticulum (ER) stress on parental tumor cells via N-glycosylation inhibition with tunicamycin. The generated immunogenic TDEs (iTDEs) contained down-regulated immunosuppressive proteins and up-regulated immune adjuvants, effectively activating dendritic cells (DCs) in vitro. Furthermore, in vivo evidence from a tumor-bearing mouse model showed that iTDEs activated DCs, enabling cytotoxic T lymphocytes (CTLs) to target tumors, and eventually established a systemic antitumor immune response. Additionally, iTDEs significantly delayed tumor recurrence in a postsurgery model compared with control groups. These findings highlight the immense potential of our strategy for utilizing TDEs to develop effective cancer vaccines.

Blood transcriptomic differences in the immune response under stressful environmental according to stocking density in pigs.

The implementation of animal welfare in the pig industry is becoming a global trend, and welfare can be improved through livestock management. In modern and intensive farming systems, it has become important to find a reasonable compromise between stocking density and productivity. The simultaneous detection of behavioral and physiological parameters is helpful when considering welfare levels for stocking density. This study aimed to confirm the effect of stocking density through transcriptome linkage. A comparison of three groups according to stocking density (low density, eight pigs and 1.0 m2 per head; normal density, eight pigs and 0.8 m2 per head; and high density, eight pigs and 0.6 m2 per head) was performed, and their transcriptomic changes were observed using the RNA-Seq method. Differentially expressed genes were identified for each comparison group (low density vs. normal density, 95 upregulated genes and 112 downregulated genes; high density vs. normal density, 133 upregulated genes and 217 downregulated genes; and high density vs. low density, 245 upregulated genes and 237 downregulated genes). Biological mechanisms according to stocking density were identified through functional annotation. T-cell differentiation and immune disease pathway enriched in the high-density group caused immune imbalance through dysregulated T-cell signaling. Moreover, oxidative stress, together with DNA damage, can lead to high susceptibility to disease. Our study confirmed the biological mechanisms through immunological expression patterns according to stocking density. The study results are expected to provide comprehensive insight into systematic operation strategies considering stocking density and biomarkers for use in welfare evaluation.

Animal welfare in the pig industry is a worldwide trend, and appropriate livestock management can improve welfare. Balancing stocking density and productivity is crucial in intensive farming systems. This study used behavioral and physiological parameters to assess welfare levels related to stocking density. The study identified biological mechanisms and immunological expression patterns influenced by stocking density by analyzing the transcriptome. These results offer comprehensive insights into operational strategies considering stocking density and biomarkers.

Disease-microenvironment modulation by bare- or engineered-exosome for rheumatoid arthritis treatment.

BACKGROUND: Exosomes are extracellular vesicles secreted by eukaryotic cells and have been extensively studied for their surface markers and internal cargo with unique functions. A deeper understanding of exosomes has allowed their application in various research areas, particularly in diagnostics and therapy. MAIN BODY: Exosomes have great potential as biomarkers and delivery vehicles for encapsulating therapeutic cargo. However, the limitations of bare exosomes, such as rapid phagocytic clearance and non-specific biodistribution after injection, pose significant challenges to their application as drug delivery systems. This review focuses on exosome-based drug delivery for treating rheumatoid arthritis, emphasizing pre/post-engineering approaches to overcome these challenges. CONCLUSION: This review will serve as an essential resource for future studies to develop novel exosome-based therapeutic approaches for rheumatoid arthritis. Overall, the review highlights the potential of exosomes as a promising therapeutic approach for rheumatoid arthritis treatment.

Effects of resistant starch on anti-obesity status and nutrient digestibility in dogs.

This study investigated the effects of corn resistant starch (RS) on the anti-obesity properties, nutrient digestibility, and blood parameters in healthy beagles. Four spayed and six castrated beagle dogs were divided into a control group (CON) with a diet comprising rice and chicken meal and a treatment group (TRT) with a diet comprising corn with an increased RS content by heating-cooling and chicken meal. All dogs in the CON and TRT groups were fed a 1.2-fold higher energy diet than the daily recommended energy requirement for 16 weeks. Throughout the study period, the body weight of dogs in CON increased, whereas no change in body weight was observed in TRT, resulting in a significant difference in body weight between the two groups at the end of the experiment. Moreover, a significant reduction in the apparent total tract digestibility was observed upon the analysis of dry matter, nitrogen-free extract, and organic matter in TRT compared with that in CON. The complete blood cell composition and biochemical parameters were within the reference range in both groups. A significant increase in the concentration of serum adiponectin was found in TRT at the end of the experiment. These results suggest that the corn RS may be beneficial for weight management owing to its reduced nutrient digestibility.

Soluble receptors for advanced glycation end-products prevent unilateral ureteral obstruction-induced renal fibrosis.

Introduction: The receptor for advanced glycation end products (RAGE) and its ligands, such as high-mobility group protein box 1 (HMGB1), play an important role in the accumulation of extracellular matrix in chronic kidney diseases with tubulointerstitial fibrosis. Blocking RAGE signaling with soluble RAGE (sRAGE) is a therapeutic candidate for renal fibrosis. Methods: NRK-52E cells were stimulated with or without HMGB1 and incubated with sRAGE in vitro. Sprague-Dawley rats were intraperitoneally treated with sRAGE after unilateral ureteral obstruction (UUO) operation in vivo. Results: HMBG1-stimulated NRK-52E cells showed increased fibronectin expression, type I collagen, α-smooth muscle actin, and connective tissue growth factor, which were attenuated by sRAGE. The mitogen-activated protein kinase (MAPK) pathway and nuclear translocation of nuclear factor kappa B (NF-κB) were enhanced in NRK-52E cells exposed to HMBG1, and sRAGE treatment alleviated the activation of the MAPK and NF-κB pathways. In the UUO rat models, sRAGE significantly ameliorated the increased renal fibronectin, type I collagen, and α-smooth muscle actin expressions. Masson's trichrome staining confirmed the anti-fibrotic effect of sRAGE in the UUO rat model. RAGE also significantly attenuated the activation of the MAPK pathway and NF-κB, as well as the increased number of infiltrated macrophages within the tubulointerstitium in the kidney of the UUO rat models. Conclusion: These findings suggest that RAGE plays a pivotal role in the pathogenesis of renal fibrosis and that its inhibition by sRAGE may be a potential therapeutic approach for renal fibrosis.

Functionally Masked Antibody to Uncouple Immune-Related Toxicities in Checkpoint Blockade Cancer Therapy.

Of the existing immunotherapy drugs in oncology, monoclonal antibodies targeting the immune checkpoint axis are preferred because of the durable responses observed in selected patients. However, the associated immune-related adverse events (irAEs), causing uncommon fatal events, often require specialized management and medication discontinuation. The study aim was to investigate our hypothesis that masking checkpoint antibodies with tumor microenvironment (TME)-responsive polymer chains can mitigate irAEs and selectively target tumors by limiting systemic exposure to patients. We devised a broadly applicable strategy that functionalizes immune checkpoint-blocking antibodies with a mildly acidic pH-cleavable poly(ethylene glycol) (PEG) shell to prevent inflammatory side effects in normal tissues. Conjugation of pH-sensitive PEG to anti-CD47 antibodies (αCD47) minimized antibody-cell interactions by inhibiting their binding ability and functionality at physiological pH, leading to prevention of αCD47-induced anemia in tumor-bearing mice. When conjugated to anti-CTLA-4 and anti-PD-1 antibodies, double checkpoint blockade-induced colitis was also ameliorated. Notably, removal of the protective shell in response to an acidic TME restored the checkpoint antibody activities, accompanied by effective tumor regression and long-term survival in the mouse model. Our results support a feasible strategy for antibody-based therapies to uncouple toxicity from efficacy and show the translational potential for cancer immunotherapy.

Curvature-sensing peptide inhibits tumour-derived exosomes for enhanced cancer immunotherapy.

Tumour-derived exosomes (T-EXOs) impede immune checkpoint blockade therapies, motivating pharmacological efforts to inhibit them. Inspired by how antiviral curvature-sensing peptides disrupt membrane-enveloped virus particles in the exosome size range, we devised a broadly useful strategy that repurposes an engineered antiviral peptide to disrupt membrane-enveloped T-EXOs for synergistic cancer immunotherapy. The membrane-targeting peptide inhibits T-EXOs from various cancer types and exhibits pH-enhanced membrane disruption relevant to the tumour microenvironment. The combination of T-EXO-disrupting peptide and programmed cell death protein-1 antibody-based immune checkpoint blockade therapy improves treatment outcomes in tumour-bearing mice. Peptide-mediated disruption of T-EXOs not only reduces levels of circulating exosomal programmed death-ligand 1, but also restores CD8+ T cell effector function, prevents premetastatic niche formation and reshapes the tumour microenvironment in vivo. Our findings demonstrate that peptide-induced T-EXO depletion can enhance cancer immunotherapy and support the potential of peptide engineering for exosome-targeting applications.

Effects of Energy and Protein Levels on Laying Performance, Egg Quality, Blood Parameters, Blood Biochemistry, and Apparent Total Tract Digestibility on Laying Hens in an Aviary System.

This study was performed to investigate the effects of apparent metabolizable energy (AMEn) and protein levels on laying performance, egg quality, blood parameters, blood biochemistry, and apparent total tract digestibility of energy and nutrients in diets fed to laying hens in an aviary system. A total of 560 Hy-Line Brown laying hens (age = 30 week) were distributed in a completely randomized experimental design in 2 × 2 factorial arrangements with 2 metabolizable energy levels (2700 and 2800 kcal AMEn/kg) and 2 protein levels (16.5 and 14.5% CP). Four treatments and four replicates of 40 birds each (stocking density = 15 birds/m2) were prepared. Results revealed no significant interaction between AMEn and CP in the diet in terms of egg production, floor eggs, broken and dirty egg production, egg mass, feed intake, and feed conversion ratio of laying hens. However, egg weight was affected. As dietary energy and CP levels (2800 kcal of AMEn/kg and 16.5% CP) increased, egg weight increased (p < 0.05). Egg weight, feed intake, and feed conversion ratio significantly differed (p < 0.05) as the energy content in the feed increased. Ether extract significantly varied (p < 0.05) as the energy content in the feed increased. In conclusion, laying performance and egg quality of Hy-Line Brown laying hens in the middle stage of egg production (30 to 50 weeks) were not affected by different dietary energy and protein levels, but feed intake decreased with an increasing level of AMEn in diets. Ether extract significantly varied as the energy content in the feed increased.

Self-immolative nanosensitizer for glutathione depletion- assisted sonodynamic therapy.

Background: Despite remarkable advances in sonodynamic therapy (SDT) of cancer, the low reactive oxygen species (ROS) quantum yield of the sonosensitizer remains a critical concern in glutathione (GSH)-overexpressing cancer cells. Methods: For enhanced SDT, we report hydrophilized self-immolative polymer (SIP)-decorated TiO2 nanoparticles (HSIPT-NPs) to achieve on-demand GSH depletion and ROS generation. Results: Upon intracellular delivery of HSIPT-NPs into hydrogen peroxide-rich cancer cells, SIP is degraded through electron transfer to produce GSH-depleting quinone methide, reprogramming GSH high cancer cells into GSH low phenotype. In the presence of ultrasound, compared to conventional TiO2 NPs, HSIPT-NPs induce significantly higher oxidative stress to cancer cells by incapacitating their antioxidant effects. SDT with HSIPT-NPs effectively inhibit tumor growth in mice via the synergistic effects of GSH depletion and ROS generation. Conclusion: On the basis of their ability to reprogram cancer cells, HSIPT-NPs offer considerable potential as a nanosensitizer for enhanced SDT.

Influence of Bile Salts and Pancreatin on Dog Food during Static In Vitro Simulation to Mimic In Vivo Digestion.

The addition of pancreatin and bile salts in different concentrations during in vitro digestion causes changes in the digestibility of crude protein (CP), fat, and dry matter (DM). The effects of bile salts and pancreatin on the digestibility of ether extract (EE), CP, and DM in developing a static in vitro digestion model for dogs were assessed using different concentrations of pancreatin (0, 1, 2.5, 5, and 10 g/L digestive solution) and bile salts (0, 2.5, 6.25, 12.5, and 25 g/L digestive solution). The data were analyzed using one-way analysis of variance. Digestibility of EE increased with the addition of bile salts (p < 0.05), whereas that of CP decreased with ≤0.25 g (1.0 g/L digestive solution) pancreatin. The digestibility of DM decreased significantly in all groups supplemented with ≥3.125 g (12.5 g/L digestive solution) bile salts and 0.25−2.5 g (1−10 g/L digestive solution) pancreatin and was the lowest with 6.25 g (25 g/L digestive solution) of bile salts (p < 0.05). These findings could facilitate the development of effective static in vitro digestion models for dogs.

Gut microbiota profiling in aged dogs after feeding pet food contained Hericium erinaceus.

Health concern of dogs is the most important issue for pet owners. People who have companied the dogs long-term provide the utmost cares for their well-being and healthy life. Recently, it was revealed that the population and types of gut microbiota affect the metabolism and immunity of the host. However, there is little information on the gut microbiome of dogs. Hericium erinaceus (H. erinaceus; HE) is one of the well-known medicinal mushrooms and has multiple bioactive components including polyphenol, ß-glucan, polysaccharides, ergothioneine, hericerin, erinacines, etc. Here we tested a pet food that contained H. erinaceus for improvement in the gut microbiota environment of aged dogs. A total of 18 dogs, each 11 years old, were utilized. For sixteen weeks, the dogs were fed with 0.4 g of H. erinaceus (HE-L), or 0.8 g (HE-H), or without H. erinaceus (CON) per body weight (kg) with daily diets (n = 6 per group). Taxonomic analysis was performed using metagenomics to investigate the difference in the gut microbiome. Resulting from principal coordinates analysis (PCoA) to confirm the distance difference between the groups, there was a significant difference between HE-H and CON due to weighted Unique fraction metric (Unifrac) distance (p = 0.047), but HE-L did not have a statistical difference compared to that of CON. Additionally, the result of Linear discriminate analysis of effect size (LEfSe) showed that phylum Bacteroidetes in HE-H and its order Bacteroidales increased, compared to that of CON, Additionally, phylum Firmicutes in HE-H, and its genera (Streptococcus, Tyzzerella) were reduced. Furthermore, at the family level, Campylobacteraceae and its genus Campylobacter in HE-H was decreased compared to that of CON. Summarily, our data demonstrated that the intake of H. erinaceus can regulate the gut microbial community in aged dogs, and an adequate supply of HE on pet diets would possibly improve immunity and anti-obesity on gut-microbiota in dogs.

Effect of Organic or Inorganic Mineral Premix in the Diet on Laying Performance of Aged Laying Hens and Eggshell Quality.

In this study, we examined the effect of diets supplemented with organic and inorganic mineral premixes on the laying performance and eggshell quality of aged laying hens. A total of 600 68-week-old Hy-Line Brown laying hens were randomly assigned to 1 of 3 dietary treatments, repeated 5 times: Mash type basal diet, basal diet supplemented with an inorganic mineral premix (1.0 g/kg), and basal diet supplemented with an organic mineral premix (1.8 g/kg). The results showed that eggshell strength was higher (p < 0.01) in the inorganic mineral diet group than in the organic mineral and basal diet groups. Further, the levels of Fe and Mn in the liver were higher (p < 0.05) in the inorganic and organic mineral diet groups than in the basal diet group. The concentrations of Fe and Mg in the spleen were different (p < 0.05) among the treatment groups, with the highest levels reported in the organic mineral premix group. The concentrations of Cu, Zn, and Mn in the eggshell were different (p < 0.05) among the groups, with the highest levels reported in the inorganic and organic mineral premix diet groups. In conclusion, a diet containing organic mineral premix improved eggshell strength and had no detrimental effect on the laying performance of aged laying hens.

Self-Assembled 4-Aminopyridine Monolayer as a Nucleation-Inducing Layer for Transparent Silver Electrodes.

The role of a self-assembled monolayer obtained by vacuum deposition of 4-aminopyridine (4-AP), a small organic molecule having amine and pyridine groups, as a metal nucleation inducer and adhesion promoter was verified, and the applicability was evaluated. 4-AP deposited to an extremely thin thickness effectively changed the substrate surface properties, increasing the nucleation density of silver (Ag) more than 3 times and eventually forming a more transparent, low-resistance Ag thin film. The optical transmittance of the Ag thin film, which was less than 60% when 4-AP was not applied, could be increased to about 77% by simply applying 4-AP, and the electrical resistance could be lowered from 37 to 14 Ω/square at the same time. Transmittance could be further improved to higher than 90% by depositing an antireflection layer for use as a transparent Ag electrode. It was also verified that 4-AP not only serves as a nucleation inducer but also contributes to improving interfacial adhesion. The Ag transparent electrode using 4-AP provided the improved performance of the organic light-emitting device due to higher transmittance, lower resistance, and surface roughness. Small organic molecules including functional groups that can be vacuum deposited, such as 4-AP, are expected to be used as surface pretreatment materials for various depositions because they can be easily patterned and can efficiently modify the surface even with extremely thin thickness.

Effect of alternative farrowing pens with temporary crating on the performance of lactating sows and their litters.

This study was performed to development the alternative farrowing pen (AFP) and to investigate performance and behavior of lactating sows and their litter. A total of 64 multiparous sows were randomly divided into two groups and were allocated to farrowing crates (FCs) and AFPs. The AFPs contained a crate and support bars that could be folded to provide the sows with extra space on day 5 postpartum. Behavior was recorded by charge-coupled device cameras and digital video recorders, and the data were scanned every 2 min to obtain an instantaneous behavioral sample. Farrowing systems did not affect feed intake, back-fat thickness, litter size and piglet weight at birth and weaning (p > 0.05). In addition, there were no differences in the number of crushed piglets between the two farrowing systems (p > 0.05). However, the weaning-to-estrus interval was shorter in the sows of the AFPs than in thous of the FCs (p < 0.05). The sows spent most of their time lying down during the lactating period, at about 80% lateral recumbency and 10%-15% ventral recumbency. The only significant differences were in the feeding and drinking behavior between sows in the two farrowing systems (p < 0.05). The FC sows displayed more feeding and drinking behavior than the AFP sows, especially in the late lactating period (p < 0.05). Piglets in the FCs tended to spend more time walking than piglets in the AFPs (p < 0.05), whereas there were no differences in suckling and lying behavior between piglets in the two farrowing systems (p > 0.05). It is concluded that the AFPs with temporary crating until day 4 postpartum did not negatively affect performance and crushed piglet compared with the FCs. It also may improve animal welfare by allowing sows to move and turn around during the lactating period. Further research is needed to find suitable housing designs to enhance productivity and animal welfare.

Dissolving microneedles for long-term storage and transdermal delivery of extracellular vesicles.

Extracellular vesicles (EVs) have shown great potential in disease diagnosis and treatment; however, their clinical applications remain challenging due to their unsatisfactory long-term stability and the lack of effective delivery strategies. In this study, we prepared human adipose stem cell-derived EV (hASC-EV)-loaded hyaluronic acid dissolving microneedles (EV@MN) to investigate the feasibility of EVs for their clinical applications. The biological activities of the EVs in this formulation were maintained for more than six months under mild storage conditions, especially at temperatures lower than 4 °C. Moreover, the EV@MN enabled precise and convenient intradermal delivery for sustained release of EVs in the dermis layer. Therefore, EV@MN significantly improved the biological functions of hASC-EVs on dermal fibroblasts by promoting syntheses of proteins for the extracellular matrix such as collagen and elastin, enhancing fibroblast proliferation, and regulating the phenotype of fibroblast, compared with other administration methods. This research revealed a possible and feasible formulation for the clinical application of EVs.

Effects of Dietary Thraustochytrid Schizochytrium sp. and Other Omega-3 Sources on Growth Performance, Carcass Characteristics, and Meat Quality of Broilers.

BACKGROUND: Looking for alternative omega-3 sources in broiler nutrition, microalgae began to get attention. We suspected that schizochytrium might play a similar role as other omega-3 sources that have been used before. METHODS: 20 g/kg schizochytrium powder (SP), salmon oil (SO), and flaxseed oil (FO) in each of the three treatment groups were supplemented in the basal diet (CON), and productive performance, carcass traits, and thigh meat quality of broilers were evaluated. RESULTS: There was a significantly higher weight gain in the SP treatment compared to the other groups, but no difference was found in feed intake and feed conversion ratio. Thiobarbituric acid reactive substance values increased during storage in all the treatments but were significantly lower for SP than for SO and FO after 7 days of storage. Among the ω-3 fatty acids (FAs), α-linolenic acid increased the most in the FO treatment, eicosapentaenoic acid increased the most in the SO treatment, and docosahexaenoic acid increased the most in the SP treatment in thigh meat, reflecting the FA composition of the lipid source diets. CONCLUSIONS: We suggested that all the dietary ω-3 FA sources could improve the FA composition of chicken meat and our results indicated the possibility to supplement broiler diets with 2% level of SP, SO, and FO as ω-3 FA sources to produce meat with a good nutritional quality for consumer's health benefits.

Functional Extracellular Vesicles for Regenerative Medicine.

The unique biological characteristics and promising clinical potential of extracellular vesicles (EVs) have galvanized EV applications for regenerative medicine. Recognized as important mediators of intercellular communication, naturally secreted EVs have the potential, as innate biotherapeutics, to promote tissue regeneration. Although EVs have emerged as novel therapeutic agents, challenges related to the clinical transition have led to further functionalization. In recent years, various engineering approaches such as preconditioning, drug loading, and surface modification have been developed to potentiate the therapeutic outcomes of EVs. Also, limitations of natural EVs have been addressed by the development of artificial EVs that offer advantages in terms of production yield and isolation methodologies. In this review, an updated overview of current techniques is provided for the functionalization of natural EVs and recent advances in artificial EVs, particularly in the scope of regenerative medicine.

Recruitment of dendritic cells using 'find-me' signaling microparticles for personalized cancer immunotherapy.

Therapeutic cancer vaccines have attracted attention because of their potential to prime cytotoxic T cells, which are highly antigen (Ag)-specific, allowing personalized cancer immunotherapy. However, because of their low immunogenicity, cancer vaccines have been used in only a few types of cancers in clinics, primarily because of the poor Ag presentation of dendritic cells (DCs). To address these limitations of cancer vaccines, we show that 'find-me' signaling polymeric microparticles (F-PMs) bearing tumor lysate as an Ag can efficiently recruit DCs and facilitate antigen presentation. When subcutaneously injected into tumor-bearing mice, F-PMs significantly increased mature DCs in tumor-draining lymph nodes by eliciting adenosine triphosphate (ATP)-induced chemotaxis, resulting in high antitumor efficacy. CD8+ cytotoxic T cells were remarkably enriched in the tumor microenvironment following co-administration of an immune checkpoint inhibitor with F-PMs. We demonstrated that F-PMs elicit a robust antitumor immune response, which may provide a promising therapeutic option for cancer treatment.