Enhancement of Immune Responses Elicited by Nanovaccines through a Cross-Presentation Pathway

Numerous studies have aimed to develop novel advanced vaccines, in part because traditional vaccines have been unsuccessful in preventing rapidly emerging and reemerging viral and bacterial infections. There is a need for an advanced vaccine delivery system to ensure the successful induction of humoral and cellular immune responses. In particular, the ability of nanovaccines to modulate intracellular antigen delivery by inducing exogenous antigens (loaded onto major histocompatibility complex class 1 molecules) in CD8+ T cells, the so-called cross-presentation pathway, has attracted a great deal of attention. Protection against viral and intracellular bacterial infections relies on cross-presentation.This review discusses the advantages, requirements, and preparation of nanovaccines, the cross-presentation mechanism, the several parameters affecting cross-presentation by nanovaccines, and future perspectives.

Bone Morphogenic Protein-2-Conjugated Three-DimensionalPrinted Poly (L-Lactic Acid) (PLLA) Scaffold is likely Promising as an Effective Bone Substitute

Bone morphogenic protein-2 (BMP-2)-conjugated three-dimensional (3-D)-printed poly (L-lactic acid)(PLLA) scaffold is likely promising as an effective bone substitute for enhancing bone regeneration of massive bone defects caused by tumor resection, traumatic injury, or congenital diseases. The authors developed a new bone substitute using a novel strategy composed of 3-D-printed PLLA scaffolds through a sequential coating of catechol-conjugated alginate (C-AL), BMP-2, and collagen (CO). The 3-D-printed PLLA scaffold was successfully obtained with 5 mm of diameter, 1 mm of thickness, 400 lm of pore size, 187–230 lm of grid thickness, and 82% of porosity. Alkaline phosphatase (ALP) activity of the BMP-2-immobilized PLLA scaffold in MC3T3-E1 and W-20-17 cells was more increased than BMP-2 itself due to the controlled release of BMP-2 from the scaffold. Tenfold new bone formation for the BMP-2-immobilized PLLA scaffold was obtained by micro-CT analysis than PLLA scaffold without BMP-2 weeks after 4 weeks of transplantation model mouse. Further another big animal model study should be performed before clinical trials.

Mucosal Vaccine Delivery Using Mucoadhesive Polymer Particulate Systems

Vaccination has been recently attracted as one of the most successful medical treatments of the prevalence of many infectious diseases. Mucosal vaccination has been interested in many researchers because mucosal immune responses play part in the first line of defense against pathogens. However, mucosal vaccination should find out an efficient antigen delivery system because the antigen should be protected from degradation and clearance, it should be targeted to mucosal sites, and it should stimulate mucosal and systemic immunity. Accordingly, mucoadhesive polymeric particles among the polymeric particles have gained much attention because they can protect the antigen from degradation, prolong the residence time of the antigen at the target site, and control the release of the loaded vaccine, and results in induction of mucosal and systemic immune responses. In this review, we discuss advances in the development of several kinds of mucoadhesive polymeric particles for mucosal vaccine delivery.

Mucosal Vaccine Delivery Using Mucoadhesive Polymer Particulate Systems

Vaccination has been recently attracted as one of the most successful medical treatments of the prevalence of many infectious diseases. Mucosal vaccination has been interested in many researchers because mucosal immune responses play part in the first line of defense against pathogens. However, mucosal vaccination should find out an efficient antigen delivery system because the antigen should be protected from degradation and clearance, it should be targeted to mucosal sites, and it should stimulate mucosal and systemic immunity. Accordingly, mucoadhesive polymeric particles among the polymeric particles have gained much attention because they can protect the antigen from degradation, prolong the residence time of the antigen at the target site, and control the release of the loaded vaccine, and results in induction of mucosal and systemic immune responses. In this review, we discuss advances in the development of several kinds of mucoadhesive polymeric particles for mucosal vaccine delivery.

Enhanced Efficacy of Immunization with a Foot-and-Mouth Disease Multi-Epitope Subunit Vaccine Using Mannan-Decorated Inulin Microparticles

BACKGROUND@#Despite the many advantages of recombinant subunit vaccines, they have critical weaknesses that include a low efficacy for promoting cellular and humoral immune responses against antigens because of their poor immunogenicity, and a rapidly cleared properties as a result of proteolytic enzymes in the body. To circumvent these problems, we developed mannan-decorated inulin acetate microparticles (M-IA MPs) that functioned as carriers and adjuvants for immunization with the recombinant foot-and-mouth disease multi-epitope subunit vaccine (M5BT). @*METHODS@#The M5BT-loaded M-IA MPs were obtained by a double-emulsion solvent-evaporation method. Their properties including morphology, size and release ability were determined by field emission scanning electron microscope, dynamic light-scattering spectrophotometer and spectrophotometer. To assess the immunization efficacy of the MPs, mice were immunized with MPs and their sera were analyzed by ELISA. @*RESULTS@#The M-IA MPs obtained by a double-emulsion solvent-evaporation method were spherical and approximately 2–3 µm, and M5BT was encapsulated in the M-IA MPs. The M5BT-loaded M-IA MPs showed higher antigen-specific IgG, IgG1, IgG2a and anti-FMDV antibodies than the M5BT-loaded IA MPs and the Freund’s adjuvant as a control. @*CONCLUSION@#The M-IA MPs showed a powerful and multifunctional polymeric system that combined two toll-like receptor agonists compared to the conventional adjuvant.

Enhanced Efficacy of Immunization with a Foot-and-Mouth Disease Multi-Epitope Subunit Vaccine Using Mannan-Decorated Inulin Microparticles

BACKGROUND@#Despite the many advantages of recombinant subunit vaccines, they have critical weaknesses that include a low efficacy for promoting cellular and humoral immune responses against antigens because of their poor immunogenicity, and a rapidly cleared properties as a result of proteolytic enzymes in the body. To circumvent these problems, we developed mannan-decorated inulin acetate microparticles (M-IA MPs) that functioned as carriers and adjuvants for immunization with the recombinant foot-and-mouth disease multi-epitope subunit vaccine (M5BT). @*METHODS@#The M5BT-loaded M-IA MPs were obtained by a double-emulsion solvent-evaporation method. Their properties including morphology, size and release ability were determined by field emission scanning electron microscope, dynamic light-scattering spectrophotometer and spectrophotometer. To assess the immunization efficacy of the MPs, mice were immunized with MPs and their sera were analyzed by ELISA. @*RESULTS@#The M-IA MPs obtained by a double-emulsion solvent-evaporation method were spherical and approximately 2–3 µm, and M5BT was encapsulated in the M-IA MPs. The M5BT-loaded M-IA MPs showed higher antigen-specific IgG, IgG1, IgG2a and anti-FMDV antibodies than the M5BT-loaded IA MPs and the Freund’s adjuvant as a control. @*CONCLUSION@#The M-IA MPs showed a powerful and multifunctional polymeric system that combined two toll-like receptor agonists compared to the conventional adjuvant.

Enhancement of antigen-specific humoral immune responses and protein solubility through conjugation of bacterial flagellin, Vibrio vulnificus FlaB, to the N-terminus of porcine epidemic diarrhea virus surface protein antigen S0

Porcine epidemic diarrhea (PED) is a highly contagious enteric swine disease. The large economic impact of PED on the swine industry worldwide has made the development of an effective PED vaccine a necessity. S0, a truncated region of the porcine epidemic diarrhea virus (PEDV) spike protein, has been suggested as a candidate antigen for PED subunit vaccines; however, poor solubility problems when the protein is expressed in Escherichia coli, and the inherent problems of subunit vaccines, such as low immunogenicity, remain. Flagellin has been widely used as a fusion partner to enhance the immunogenicity and solubility of many difficult-to-express proteins; however, the conjugation effect of flagellin varies depending on the target antigen or the position of the fusion placement. Here, we conjugated flagellin, Vibrio vulnificus FlaB, to the N- and C-termini of S0 and evaluated the ability of the fusion to enhance the solubility and immunogenicity of S0. Flagellin conjugation in the presence of the trigger factor chaperone tig greatly improved the solubility of the fusion protein (up to 99%) regardless of its conjugation position. Of importance, flagellin conjugated to the N-terminus of S0 significantly enhanced S0-specific humoral immune responses compared to other recombinant antigens in Balb/c mice. The mechanism of this phenomenon was investigated through in vitro and in vivo studies. These findings provide important information for the development of a novel PED vaccine and flagellin-based immunotherapeutics.

Updates in molecular imaging techniques

No abstract available.

Updates in Cartilage Tissue Regeneration

No abstract available.

Injectable Hydrogels for Regenerative Medicine

No abstract available.

Injectable Biomaterials in Plastic and Reconstructive Surgery: A Review of the Current Status

BACKGROUND: Injectable biomaterials have attracted increasing attention for volume restoration and tissue regeneration. The main aim of this review is to discuss the current status of the injectable biomaterials for correction of tissue defects in plastic and reconstructive surgery. METHODS: Requirements of injectable biomaterials, mechanism of in situ gelation, characteristics, and the combinational usage of adipose-derived stem cells (ADSCs) and growth factors were reviewed. RESULTS: The ideal injectable biomaterials should be biocompatible, non-toxic, easy to use, and cost-effective. Additionally, it should possess adequate mechanical properties and stability. In situ gelation method includes physical, chemical, enzymatic and photo-initiated methods. Natural and synthetic biomaterials carry their pros and cons due to their inherent properties. The combined use of ADSCs and growth factors provides enhanced potential for adipose tissue regeneration. CONCLUSION: The usage of injectable biomaterials has been increasing for the tissue restoration and regeneration. The future of incorporating ADSCs and growth factors into the injectable biomaterials is promising.

Oral Immunization of FMDV Vaccine Using pH-Sensitive and Mucoadhesive Thiolated Cellulose Acetate Phthalate Microparticles

Several barriers such as gastric pH, enzymatic degradation and rapid transit should be overcome to orally deliver antigens for taking up by epithelial microfold cells in Peyer's patches of small intestine. To solve the above mentioned problems, we designed pH-sensitive and mucoadhesive polymeric microparticles (MPs) prepared by double emulsion technique using cellulose acetate phthalate (CAP) to enhance immune response of foot-and-mouth disease (FMD) virus (FMDV) subunit vaccine. Thiolation of CAP improved mucoadhesive property of CAP to prolong the MPs transit time through the gastrointestinal tract. Thiolated CAP (T-CAP) also slowed down antigen release in acidic pH of stomach but released more antigens in neutral pH of small intestine due to the pH-sensitivity of the T-CAP. Oral immunization of a chimerical multi-epitope recombinant protein as the FMD subunit vaccine via T-CAP MPs effectively delivered the vaccine to Peyer's patches eliciting mucosal IgA response. It will make a step forward into a promising oral subunit vaccine development in livestock industry.

Drug- and Gene-eluting Stents for Preventing Coronary Restenosis / 전남의대학술지

Coronary artery disease (CAD) has been reported to be a major cause of death worldwide. Current treatment methods include atherectomy, coronary angioplasty (as a percutaneous coronary intervention), and coronary artery bypass. Among them, the insertion of stents into the coronary artery is one of the commonly used methods for CAD, although the formation of in-stent restenosis (ISR) is a major drawback, demanding improvement in stent technology. Stents can be improved using the delivery of DNA, siRNA, and miRNA rather than anti-inflammatory/anti-thrombotic drugs. In particular, genes that could interfere with the development of plaque around infected regions are conjugated on the stent surface to inhibit neointimal formation. Despite their potential benefits, it is necessary to explore the various properties of gene-eluting stents. Furthermore, multifunctional electronic stents that can be used as a biosensor and deliver drug- or gene-based on physiological condition will be a very promising way to the successful treatment of ISR. In this review, we have discussed the molecular mechanism of restenosis, the use of drug- and gene-eluting stents, and the possible roles that these stents have in the prevention and treatment of coronary restenosis. Further, we have explained how multifunctional electronic stents could be used as a biosensor and deliver drugs based on physiological conditions.

Drug- and Gene-eluting Stents for Preventing Coronary Restenosis / 전남의대학술지

Coronary artery disease (CAD) has been reported to be a major cause of death worldwide. Current treatment methods include atherectomy, coronary angioplasty (as a percutaneous coronary intervention), and coronary artery bypass. Among them, the insertion of stents into the coronary artery is one of the commonly used methods for CAD, although the formation of in-stent restenosis (ISR) is a major drawback, demanding improvement in stent technology. Stents can be improved using the delivery of DNA, siRNA, and miRNA rather than anti-inflammatory/anti-thrombotic drugs. In particular, genes that could interfere with the development of plaque around infected regions are conjugated on the stent surface to inhibit neointimal formation. Despite their potential benefits, it is necessary to explore the various properties of gene-eluting stents. Furthermore, multifunctional electronic stents that can be used as a biosensor and deliver drug- or gene-based on physiological condition will be a very promising way to the successful treatment of ISR. In this review, we have discussed the molecular mechanism of restenosis, the use of drug- and gene-eluting stents, and the possible roles that these stents have in the prevention and treatment of coronary restenosis. Further, we have explained how multifunctional electronic stents could be used as a biosensor and deliver drugs based on physiological conditions.

Local Delivery of CTGF siRNA with Poly(sorbitol-co-PEI) Reduces Scar Contraction in Cutaneous Wound Healing

Healing process in scarring inevitably produces a considerable amount of non-organized dense collagen-rich matrix called scar thus impairing the native structure of skin. Connective tissue growth factor (CTGF) overexpression within healing tissues is known to play an imperative role in collagen production stimulated by transforming growth factor-beta in cutaneous wound healing. Undoubtedly, the knockdown of CTGF expression through siRNA-mediated gene silencing could simply impede the scarring process. However, the less stability and low transfection of siRNAs themselves urge a safe carrier to protect and transfect them into cells at a high rate avoiding toxicities. Here, we developed a degradable poly(sorbitol-co-PEI) (PSPEI), prepared by polymerization of sorbitol diacrylate with low molecular weight polyethylenimine, which has high transfection efficiency but low cytotoxicity, and utilized it in siCTGF delivery to silence the expression of CTGF in an animal model of cutaneous wound healing. Unlike contracted scar in normal healing, there was no or less contraction in the healed skin of mice treated with siCTGF using PSPEI. Histologically, the healed tissues also had distinct papillary structures and dense irregular connective tissues that were lacking in the control scar tissues. This study exemplifies a successful treatment of cutaneous wound healing using a polymer system coupled with RNA interference. Hence, the approach holds a great promise for developing new treatments with novel targets in regenerative medicines.

Thanks to the Reviewers of Tissue Engineering and Regenerative Medicine

No abstract available.

Three-Dimensional Printing in Tissue Engineering and Regenerative Medicine

No abstract available.

Gene Therapy for Bone Tissue Engineering

Gene therapy holds a great promise and has been extensively investigated to improve bone formation and regeneration therapies in bone tissue engineering. A variety of osteogenic genes can be delivered by combining different vectors (viral or non-viral), scaffolds and delivery methodologies. Ex vivo & in vivo gene enhanced tissue engineering approaches have led to successful osteogenic differentiation and bone formation. In this article, we review recent advances of gene therapy-based bone tissue engineering discussing strengths and weaknesses of various strategies as well as general overview of gene therapy.

IrreVersible Gel Tansformation of Injectavble Intraocular Lens by Photoinitiator and UV Irradiation in Rabbits

PURPOSE: This study was designed to induce irreVersible gel formation of poloxamer, the thermosensitive polymer hydrogel, by using photoinitiator and UV irradiation, and to verify the biocompatibility and usability of poloxamer as an injectable intraocular lens material through long-term observation in vivo. METHODS: Endocapsular phacoemulsification of lens was performed in rabbits and 25% poloxamer mixed with various concentrations of photoinitiator was injected into the capsular bag through a small capsulorhexis site. Then, the whole eye was irradiated with UV light for 5 minutes. The irreversibility and transparency of the post-operative poloxamer and the effects on the conjunctiva, cornea, iris, vitreous humor and retina were observed. RESULTS: As the results of this experiment using poloxamer 25% and photoinitiator 0.01%, the poloxamer remained transparent in the lens capsule for more than six months after the operation. No inflammatory response or toxicity was observed on the conjunctiva, cornea, iris, vitreous humor or retina. CONCLUSIONS: This study demonstrated the possibility of poloxamer as a new material for the injectable intraocular lens. Further study, however, is necessary.

Nuclear Imaging Evaluation of Galactosylation of Chitosan / 대한핵의학회잡지

PURPOSE: Chitosan has been studied as a non-viral gene delivery vector, drug delivery carrier, metal chelater, food additive, and radiopharmaceutical, among other things. Recently, galactose-graft chitosan was studied as a non-viral gene and drug delivery vector to target hepatocytes. The aim of this study was to investigate the usefulness of nuclear imaging for in vivo evaluation of targeting the hepatocyte by galactose grafting. METHODS AND MATERIALS: Galactosyl methylated chitosan (GMC) was produced by methylation to lactobionic acid coupled chitosan. Cytotoxicity of 99mTc-GMC was determined by MTT assay. Rabbits were injected via their auricular vein with 99mTc-GMC and 99mTc-methylated chitosan (MC), the latter of which does not contain a galactose group, and images were acquired with a gamma camera equipped with a parallel hole collimator. The composition of the galactose group in galactosylated chitosan (GC), as well as the tri-, di-, or mono-methylation of GMC, was confirmed by NMR spectroscopy. RESULTS: The results of MTT assay indicated that 99mTc-GMC was non-toxic. 99mTc-GMC specifically accumulated in the liver within 10 minutes of injection and maintained high hepatic uptake. In contrast, 99mTc-MC showed faint liver uptake. 99mTc-GMC scintigraphy of rabbits showed that the galactose ligand principally targeted the liver while the chitosan functionalities led to excretion through the urinary system. CONCLUSION: Bioconjugation with a specific ligand endows some degree of targetability to an administered molecule or drug, as in the case of galactose for hepatocyte in vivo, and evaluating said targetabililty is a clear example of the great benefit proffered by nuclear imaging.