Osteoporotic Bone Regeneration via Plenished Biomimetic PLGA Scaffold with Sequential Release System.

Achieving satisfactory bone tissue regeneration in osteoporotic patients with ordinary biomaterials is challenging because of the decreased bone mineral density and aberrant bone microenvironment. In addressing this issue, a biomimetic scaffold (PMEH/SP), incorporating 4-hexylresorcinol (4HR), and substance P (SP) into the poly(lactic-go-glycolic acid) (PLGA) scaffold with magnesium hydroxide (M) and extracellular matrix (E) is introduced, enabling the consecutive release of bioactive agents. 4HR and SP induced the phosphorylation of p38 MAPK and ERK in human umbilical vein endothelial cells (HUVECs), thereby upregulating VEGF expression level. The migration and tube-forming ability of endothelial cells can be promoted by the scaffold, which accelerates the formation and maturation of the bone. Moreover, 4HR played a crucial role in the inhibition of osteoclastogenesis by interrupting the IκB/NF-κB signaling pathway and exhibiting SP, thereby enhancing the migration and angiogenesis of HUVECs. Based on such a synergistic effect, osteoporosis can be suppressed, and bone regeneration can be achieved by inhibiting the RANKL pathway in vitro and in vivo, which is a commonly known mechanism of bone physiology. Therefore, the study presents a promising approach for developing a multifunctional regenerative material for sophisticated osteoporotic bone regeneration.

Combinatory Nanovesicle with siRNA-Loaded Extracellular Vesicle and IGF-1 for Osteoarthritis Treatments.

Extracellular vesicles (EVs) have been found to have the characteristics of their parent cells. Based on the characteristics of these EVs, various studies on disease treatment using mesenchymal stem cell (MSC)-derived EVs with regenerative activity have been actively conducted. The therapeutic nature of MSC-derived EVs has been shown in several studies, but in recent years, there have been many efforts to functionalize EVs to give them more potent therapeutic effects. Strategies for functionalizing EVs include endogenous and exogenous methods. In this study, human umbilical cord MSC (UCMSC)-derived EVs were selected for optimum OA treatments with expectation via bioinformatics analysis based on antibody array. And we created a novel nanovesicle system called the IGF-si-EV, which has the properties of both cartilage regeneration and long-term retention in the lesion site, attaching positively charged insulin-like growth factor-1 (IGF-1) to the surface of the UCMSC-derived Evs carrying siRNA, which inhibits MMP13. The downregulation of inflammation-related cytokine (MMP13, NF-kB, and IL-6) and the upregulation of cartilage-regeneration-related factors (Col2, Acan) were achieved with IGF-si-EV. Moreover, the ability of IGF-si-EV to remain in the lesion site for a long time has been proven through an ex vivo system. Collectively, the final constructed IGF-si-EV can be proposed as an effective OA treatment through its successful MMP13 inhibition, chondroprotective effect, and cartilage adhesion ability. We also believe that this EV-based nanoparticle-manufacturing technology can be applied as a platform technology for various diseases.

Systemic Delivery of a STING Agonist-Loaded Positively Charged Liposome Selectively Targets Tumor Immune Microenvironment and Suppresses Tumor Angiogenesis.

Although stimulator of interferon genes (STING) agonists has shown great promise in preclinical studies, the clinical development of STING agonist therapy is challenged by its limited systemic delivery. Here, positively charged fusogenic liposomes loaded with a STING agonist (PoSTING) are designed for systemic delivery and to preferentially target the tumor microenvironment. When PoSTING is administered intravenously, it selectively targets not only tumor cells but also immune and tumor endothelial cells (ECs). In particular, delivery of STING agonists to tumor ECs normalizes abnormal tumor vasculatures, induces intratumoral STING activation, and elicits robust anti-tumor T cell immunity within the tumor microenvironment. Therefore, PoSTING can be used as a systemic delivery platform to overcome the limitations of using STING agonists in clinical trials.

Combination of Metal-Phenolic Network-Based Immunoactive Nanoparticles and Bipolar Irreversible Electroporation for Effective Cancer Immunotherapy.

To circumvent the limitations of conventional cancer immunotherapy, it is critical to prime antigen-presenting cells (APCs) to initiate the cancer-immune cycle. Here, the authors develop a metal-phenolic network (MPN)-based immunoactive nanoparticle in combination with irreversible electroporation (IRE) for an effective cancer immunotherapy. The MPN nanoparticles are synthesized by coordinating tannic acid with manganese (Mn) ions, and subsequent coating with CpG-oligodeoxynucleotides (CpG-ODNs) via hydrogen bonding. The CpG-ODN-coated Mn-phenolic network (CMP) nanoparticles are effectively internalized into macrophages, a type of APCs, and successfully trigger M1 polarization to promote release of proinflammatory cytokines. Notably, the CMP nanoparticles demonstrate an extended retention time period than the free CpG-ODN in the tumor. The tumor microenvironment tailored bipolar IRE, enhances the therapeutic efficacy by significantly broadening the ablation zone, which further increases immunogenic cell death (ICD). Ultimately, the simultaneous CMP nanoparticles and IRE treatment successfully inhibit tumor growth and prolong survival in a mouse tumor model. Thus, CMP nanoparticles are empowered with Mn and CpG-ODN immunomodulators and the tumor microenvironment tailored bipolar IRE will be a new tool for effective cancer immunotherapy to treat intractable malignancies.

The Upregulation of Regenerative Activity for Extracellular Vesicles with Melatonin Modulation in Chemically Defined Media.

Extracellular vesicles (EVs) derived from human mesenchymal stem cells (hMSCs) have been widely known to have therapeutic effects by representing characteristics of the origin cells as an alternative for cell-based therapeutics. Major limitations of EVs for clinical applications include low production yields, unknown effects from serum impurities, and relatively low bioactivities against dose. In this study, we proposed a cell modulation method with melatonin for human umbilical cord MSCs (hUCMSCs) cultured in serum-free chemically defined media (CDM) to eliminate the effects of serum-derived impurities and promote regeneration-related activities. miRNAs highly associated with regeneration were selected and the expression levels of them were comparatively analyzed among various types of EVs depending on culture conditions. The EVs derived from melatonin-stimulated hUCMSCs in CDM (CDM mEVs) showed the highest expression levels of regeneration-related miRNAs, and 7 times more hsa-let-7b-5p, 5.6 times more hsa-miR-23a-3p, and 5.7 times more hsa-miR-100-5p than others, respectively. In addition, the upregulation of various functionalities, such as wound healing, angiogenesis, anti-inflammation, ROS scavenging, and anti-apoptosis, were proven using in vitro assays by simulating the characteristics of EVs with bioinformatics analysis. The present results suggest that the highly regenerative properties of hUCMSC-derived EVs were accomplished with melatonin stimulation in CDM and provided the potential for clinical uses of EVs.

Human Mesenchymal Stem Cell-Derived Extracellular Vesicles Promote Neural Differentiation of Neural Progenitor Cells.

Mesenchymal stem cells (MSCs) have been adopted in various preclinical and clinical studies because of their multipotency and low immunogenicity. However, numerous obstacles relating to safety issues remain. Therefore, MSC-derived extracellular vesicles (EVs) have been recently employed. EVs are nano-sized endoplasmic reticulum particles generated and released in cells that have similar biological functions to their origin cells. EVs act as cargo for bioactive molecules such as proteins and genetic materials and facilitate tissue regeneration. EVs obtained from adipose-derived MSC (ADMSC) also have neuroprotective and neurogenesis effects. On the basis of the versatile effects of EVs, we aimed to enhance the neural differentiation ability of ADMSC-derived EVs by elucidating the neurogenic-differentiation process. ADMSC-derived EVs isolated from neurogenesis conditioned media (differentiated EVs, dEVs) increased neurogenic ability by altering innate microRNA expression and cytokine composition. Consequently, dEVs promoted neuronal differentiation of neural progenitor cells in vitro, suggesting that dEVs are a prospective candidate for EV-based neurological disorder regeneration therapy.

Recent trends in cell membrane-cloaked nanoparticles for therapeutic applications.

Synthetic nanoparticles are extensively utilized in various biomedical engineering fields because of their unique physicochemical properties. However, their exogenous characteristics result in synthetic nanosystem invaders that easily induce the passive immune clearance mechanism, thereby increasing the retention effect caused by reticuloendothelial system (RES), resulting in low therapeutic efficacy and toxic effects. Recently, a cell membrane cloaking has been emerging technique as a novel interfacing approach from the biological/immunological perspective. This has been considered as useful technique for improving the performance of synthetic nanocarriers in vivo. By cell membrane cloaking, nanoparticles acquire the biological functions of natural cell membranes due to the presence of membrane-anchored proteins, antigens, and immunological moieties as well as physicochemical property of natural cell membrane. Due to cell membrane cloaking, the derived biological properties and functions of nanoparticles such as their immunosuppressive capability, long circulation time, and disease targeting ability have enhanced their future potential in biomedicine. Here, we review the cell membrane-cloaked nanosystems, highlight their novelty, introduce the preparation and characterization methods with relevant biomedical applications, and describe the prospects for using this novel biomimetic system that was developed from a combination of cell membranes and synthetic nanomaterials.

Enhancing Neurogenesis of Neural Stem Cells Using Homogeneous Nanohole Pattern-Modified Conductive Platform.

Biocompatible platforms, wherein cells attach and grow, are important for controlling cytoskeletal dynamics and steering stem cell functions, including differentiation. Among various components, membrane integrins play a key role in focal adhesion of cells (18-20 nm in size) and are, thus, highly sensitive to the nanotopographical features of underlying substrates. Hence, it is necessary to develop a platform/technique that can provide high flexibility in controlling nanostructure sizes. We report a platform modified with homogeneous nanohole patterns, effective in guiding neurogenesis of mouse neural stem cells (mNSCs). Sizes of nanoholes were easily generated and varied using laser interference lithography (LIL), by changing the incident angles of light interference on substrates. Among three different nanohole patterns fabricated on conductive transparent electrodes, 500 nm-sized nanoholes showed the best performance for cell adhesion and spreading, based on F-actin and lamellipodia/filopodia expression. Enhanced biocompatibility and cell adhesion of these nanohole patterns ultimately resulted in the enhanced neurogenesis of mNSCs, based on the mRNAs expression level of the mNSCs marker and several neuronal markers. Therefore, platforms modified with homogeneous nanohole patterns fabricated by LIL are promising for the precise tuning of nanostructures in tissue culture platforms and useful for controlling various differentiation lineages of stem cells.

Nitric Oxide Releasing Coronary Stent: A New Approach Using Layer-by-Layer Coating and Liposomal Encapsulation.

The sustained or controlled release of nitric oxide (NO) can be the most promising approach for the suppression or prevention of restenosis and thrombosis caused by stent implantation. The aim of this study is to investigate the feasibility in the potential use of layer-by-layer (LBL) coating with a NO donor-containing liposomes to control the release rate of NO from a metallic stent. Microscopic observation and surface characterizations of LBL-modified stents demonstrate successful LBL coating with liposomes on a stent. Release profiles of NO show that the release rate is sustained up to 5 d. In vitro cell study demonstrates that NO release significantly enhances endothelial cell proliferation, whereas it markedly inhibits smooth muscle cell proliferation. Finally, in vivo study conducted with a porcine coronary injury model proves the therapeutic efficacy of the NO-releasing stents coated by liposomal LBL technique, supported by improved results in luminal healing, inflammation, and neointimal thickening except thrombo-resistant effect. As a result, all these results demonstrate that highly optimized release rate and therapeutic dose of NO can be achieved by LBL coating and liposomal encapsulation, followed by significantly efficacious outcome in vivo.

A poly(lactide) stereocomplex structure with modified magnesium oxide and its effects in enhancing the mechanical properties and suppressing inflammation.

Biodegradable polymers such as poly(L-lactide) (PLLA) have been widely utilized as materials for biomedical applications. However, the relatively poor mechanical properties of PLLA and its acid-induced cell inflammation brought about by the acidic byproducts during biodegradation pose severe problems. In this study, these drawbacks of PLLA are addressed using a stereocomplex structure, where oligo-D-lactide-grafted magnesium hydroxide (MgO-ODLA) is synthesized by grafting d-lactide onto the surface of magnesium hydroxide, which is then blended with a PLLA film. The structure, morphology, pH change, thermal and mechanical properties, in-vitro cytotoxicity, and inflammation effect of the MgO-ODLAs and their PLLA composites are evaluated through various analyses. The PLLA/MgO70-ODLA30 (0-20 wt%) composite with a stereocomplex structure shows a 20% increase in its tensile strength and an improvement in the modulus compared to its oligo-L-lactide (PLLA/MgO70-OLLA30) counterpart. The interfacial interaction parameter of PLLA/MgO70-ODLA30 (5.459) has superior properties to those of PLLA/MgO70-OLLA30 (4.013) and PLLA/Mg(OH)2 (1.774). The cell cytotoxicity and acid-induced inflammatory response are suppressed by the neutralizing effect of the MgO-ODLAs. In addition, the inflammatory problem caused by the rapid acidification of the stereocomplex structure is also addressed. As a result, the stereocomplex structure of the MgO-ODLA/PLLA composite can be used to overcome the problems associated with the biomedical applications of PLLA films.

Multi-lineage differentiation of human mesenchymal stromal cells on the biophysical microenvironment of cell-derived matrix.

We obtained fibroblast- (FDM) and preosteoblast- (PDM) derived matrices in vitro from their respective cells. Our hypothesis was that these naturally occurring cell-derived matrices (CDMs) would provide a better microenvironment for the multi-lineage differentiation of human mesenchymal stromal cells (hMSCs) than those based on traditional single-protein-based platforms. Cells cultured for 5-6 days were decellularized with detergents and enzymes. The resulting matrices showed a fibrillar surface texture. Under osteogenic conditions, human bone-marrow-derived stromal cells (HS-5) exhibited higher amounts of both mineralized nodule formation and alkaline phosphatase (ALP) expression than those cultured on plastic or gelatin. Osteogenic markers (Col I, osteopontin, and cbfa1) and ALP activity from cells cultured on PDM were notably upregulated at 4 weeks. The use of FDM significantly improved the cellular expression of chondrogenic markers (Sox 9 and Col II), while downregulating that of Col I at 4 weeks. Both CDMs were more effective in inducing cellular synthesis of glycosaminoglycan content than control substrates. We also investigated the effect of matrix surface texture on hMSC (PT-2501) differentiation; soluble matrix (S-matrix)-coated substrates exhibited a localized fibronectin (FN) alignment, whereas natural matrix (N-matrix)-coated substrates preserved the naturally formed FN fibrillar alignment. hMSCs cultured for 4 weeks on N-matrices under osteogenic or chondrogenic conditions deposited a greater amount of calcium and proteoglycan than those cultured on S-matrices as assessed by von Kossa and Safranin O staining. In contrast to the expression levels of lineage-specific markers for cells cultured on gelatin, FN, or S-matrices, those cultured on N-matrices yielded highly upregulated levels. This study demonstrates not only the capacity of CDM for being an effective inductive template for the multi-lineage differentiation of hMSCs, but also the critical biophysical role that the matrix fibrillar texture itself plays on the induction of stem cell differentiation.

Effect of solvent on drug release and a spray-coated matrix of a sirolimus-eluting stent coated with poly(lactic-co-glycolic acid).

Sirolimus (SRL) release from the biodegradable poly(l-lactic-co-glycolic acid) (PLGA) matrix was investigated for the application of drug-eluting stents (DES). In particular, this study focused on whether various organic solvents affect the interaction between SRL and PLGA and the formation of microstructures during ultrasonic coating. The SRL-loaded PLGA coated by tetrahydrofuran or acetone showed a significant initial burst, whereas that from acetonitrile was constantly released during a period of 21 days. On the basis of these results, the interactions at the molecular level of SRL with the polymer matrix were estimated according to various organic solvents. Although the topographies of the coated surface were obviously different, the correlation between surface roughness and SRL release was very poor. Irrespective of organic solvents, FT-IR data showed significantly weak SRL-PLGA interactions. From the result of wide-angle X-ray diffraction, it was confirmed that SRL was dispersed in an amorphous state in the polymer matrix after ultrasonic coating. The glass-transition temperature was also influenced by organic solvents, resulting in a plasticizing effect. The particle size of SRL appeared to determine the release profile from the PLGA matrix, which was the combination of diffusion and polymer degradation at an SRL size of more than 800 nm and the Fickian release at that of less than 300 nm. Therefore, organic solvents can lead to a heterogeneous microstructure in the SRL-loaded PLGA matrix, which is at or near the surface, consisting of aggregated drug- and polymer-rich regions. It is expected that the drug release can be controlled by physicochemical properties of organic solvents, and this study can be used effectively for localized drug release in biomedical devices such as drug-eluting stents.

Reinforcement of interfacial adhesion of a coated polymer layer on a cobalt-chromium surface for drug-eluting stents.

During the balloon expansion of several commercially available drug-eluting stents, various types of defects in the polymer layer have been observed. The aim of this study is to prevent these defects by increasing the interfacial adhesion between the metal substrate and the drug-in-polymer matrix using poly(caprolactone) (PCL) brushes onto a cobalt-chromium (Co-Cr or CC) alloy surface. The chemical modification of the Co-Cr surface was accomplished by grafting ricinoleic acid (RA) onto the metal substrate followed by surface-initiated ring opening polymerization of ε-caprolactone. The unmodified, RA-grafted (CC-RA), and PCL-grafted Co-Cr substrates (CC-RA-PCL3D and CC-RA-PCL6D) were characterized by various surface analyses. Poly(d,l-lactide) containing sirolimus was spray coated onto the unmodified and modified substrates. The adhesion property of the polymer coating on the PCL-grafted surfaces was improved compared to those of other samples. Among all of the drug-in-polymer coated samples, both CC-RA-PCL3D and CC-RA-PCL6D exhibited a stabilized drug release profile over 49 days. It was also revealed that CC-RA-PCL6D showed the slowest drug release of all the samples. On the basis of these results, the proposed nanocoupling method has shown not only improved adhesion of the drug-in-polymer matrix to the Co-Cr substrate but also controlled drug release.

Mussel-mimetic protein-based adhesive hydrogel.

Hydrogel systems based on cross-linked polymeric materials which could provide both adhesion and cohesion in wet environment have been considered as a promising formulation of tissue adhesives. Inspired by marine mussel adhesion, many researchers have tried to exploit the 3,4-dihydroxyphenylalanine (DOPA) molecule as a cross-linking mediator of synthetic polymer-based hydrogels which is known to be able to achieve cohesive hardening as well as adhesive bonding with diverse surfaces. Beside DOPA residue, composition of other amino acid residues and structure of mussel adhesive proteins (MAPs) have also been considered important elements for mussel adhesion. Herein, we represent a novel protein-based hydrogel system using DOPA-containing recombinant MAP. Gelation can be achieved using both oxdiation-induced DOPA quinone-mediated covalent and Fe(3+)-mediated coordinative noncovalent cross-linking. Fe(3+)-mediated hydrogels show deformable and self-healing viscoelastic behavior in rheological analysis, which is also well-reflected in bulk adhesion strength measurement. Quinone-mediated hydrogel has higher cohesive strength and can provide sufficient gelation time for easier handling. Collectively, our newly developed MAP hydrogel can potentially be used as tissue adhesive and sealant for future applications.

Multiple treatments with human embryonic stem cell-derived mesenchymal progenitor cells preserved the fertility and ovarian function of perimenopausal mice undergoing natural aging.

OBJECTIVES: Currently, no approved stem cell-based therapies for preserving ovarian function during aging. To solve this problem, we developed a long-term treatment for human embryonic stem cell-derived mesenchymal progenitor cells (hESC-MPCs). We investigated whether the cells retained their ability to resist ovarian aging, which leads to delayed reproductive senescence. MATERIALS AND METHODS: In a middle-aged female model undergoing natural aging, we analyzed whether hESC-MPCs benefit the long-term maintenance of reproductive fecundity and ovarian reservoirs and how their transplantation regulates ovarian function. RESULTS: The number of primordial follicles and mice with regular estrous cycles were increased in perimenopausal mice who underwent multiple introductions of hESC-MPCs compared to age-matched controls. The estradiol levels in the hESC-MPCs group were restored to those in the young and adult groups. Embryonic development and live birth rates were higher in the hESC-MPC group than in the control group, suggesting that hESC-MPCs delayed ovarian senescence. In addition to their direct effects on the ovary, multiple-treatments with hESC-MPCs reduced ovarian fibrosis by downregulating inflammation and fibrosis-related genes via the suppression of myeloid-derived suppressor cells (MDSCs) produced in the bone marrow. CONCLUSIONS: Multiple introductions of hESC-MPCs could be a useful approach to prevent female reproductive senescence and that these cells are promising sources for cell therapy to postpone the ovarian aging and retain fecundity in perimenopausal women.

Bulk Modification with Inorganic Particles and Immobilization of Extracellular Vesicles onto PDO Composite for Facial Rejuvenation.

BACKGROUND: The skin, a vital organ protecting against microorganisms and dehydration, undergoes structural decline with aging, leading to visible issues such as wrinkles and sagging. Reduced blood vessels exacerbate vulnerability, hindering optimal cellular function and compromising skin health. Polydioxanone (PDO) biomaterials address aging concerns but produce acidic byproducts, causing inflammation. Inorganic particles and nitric oxide (NO) play crucial roles in inhibiting inflammation and promoting skin regeneration. Stem cell-derived extracellular vesicles (EVs) contribute to intercellular communication, offering the potential to enhance cell functions. The study proposes a method to enhance PDO-based medical devices by incorporating inorganic particles and immobilizing EVs, focusing on facial rejuvenation, anti-inflammatory response, collagen formation, and angiogenesis. METHOD: PDO composites with inorganic particles such as magnesium hydroxide (MH) and zinc oxide (ZO) were prepared and followed by EV immobilization. Comprehensive characterization included biocompatibility, anti-inflammation, collagen formation ability, and angiogenesis ability. RESULTS: Bulk-modified PDO composites demonstrated even dispersion of inorganic particles, pH neutralization, and enhanced biocompatibility. EVs immobilized on the composite surface exhibited spherical morphology. Inflammation-related gene expressions decreased, emphasizing anti-inflammatory effects. Collagen-related gene and protein expressions increased, showcasing collagen formation ability. In addition, angiogenic capabilities were notably improved, indicating potential for skin rejuvenation. CONCLUSION: The study successfully developed and characterized PDO composites with inorganic particles and EVs, demonstrating promising attributes for medical applications. These composites exhibit biocompatibility, anti-inflammatory properties, collagen formation ability, and angiogenic potential, suggesting their utility in skin rejuvenation and tissue engineering. Further research and clinical validation are essential.

Injectable Microparticle-containing hydrogel with controlled release of bioactive molecules for facial rejuvenation.

The skin is the largest organ and a crucial barrier for protection against various intrinsic and extrinsic factors. As we age, the skin's components become more vulnerable to damage, forming wrinkles. Among different procedures, hyaluronic acid-based hydrogel has been extensively utilized for skin regeneration and reducing wrinkles. However, it has limitations like low retention and weak mechanical properties. In this study, we suggested the poly(l-lactic acid) (PLLA) microparticles containing alkaline magnesium hydroxide and nitric oxide-generating zinc oxide and rejuvenative hyaluronic acid (HA) hydrogels including these functional microparticles and asiaticoside, creating a novel delivery system for skin rejuvenation and regeneration. The fabricated rejuvenative hydrogels have exhibited enhanced biocompatibility, pH neutralization, reactive oxygen species scavenging, collagen biosynthesis, and angiogenesis capabilities in vitro and in vivo. Additionally, an excellent volume retention ability was demonstrated due to the numerous hydrogen bonds that formed between hyaluronic acid and asiaticoside. Overall, our advanced injectable hydrogel containing functional microparticles, with controlled release of bioactive molecules, has a significant potential for enhancing the regeneration and rejuvenation of the skin.

Therapeutic potential of luteolin-loaded poly(lactic-co-glycolic acid)/modified magnesium hydroxide microsphere in functional thermosensitive hydrogel for treating neuropathic pain.

Neuropathic pain (NP) is a debilitating condition stemming from damage to the somatosensory system frequently caused by nerve injuries or lesions. While existing treatments are widely employed, they often lead to side effects and lack specificity. This study aimed to alleviate NP by developing an innovative sustained-release thermosensitive hydrogel system. The system incorporates hyaluronic acid (HA)/Pluronic F127 injectable hydrogel and bupivacaine (Bup, B) in combination with poly(lactic-co-glycolic acid; PLGA)/modified magnesium hydroxide (MH)/luteolin (Lut; PML) microspheres (PML@B/Gel). The PML@B/Gel was designed for localized and prolonged co-delivery of Bup and Lut as an anesthetic and anti-inflammatory agent, respectively. Our studies demonstrated that PML@B/Gel had exceptional biocompatibility, anti-inflammatory, and antioxidant properties. In addition, it exhibited efficient pain relief in in vitro cellular assays. Moreover, this functional hydrogel showed substantial sustained drug release while diminishing microglial activation. Consequently, it effectively mitigated mechanical allodynia and thermal hyperalgesia in in vivo rat models of chronic constriction injury (CCI). Based on our research findings, PML@B/Gel emerges as a promising therapeutic approach for the protracted treatment of NP.

Extracellular vesicle encapsulated nicotinamide delivered via a trans-scleral route provides retinal ganglion cell neuroprotection.

The progressive and irreversible degeneration of retinal ganglion cells (RGCs) and their axons is the major characteristic of glaucoma, a leading cause of irreversible blindness worldwide. Nicotinamide adenine dinucleotide (NAD) is a cofactor and metabolite of redox reaction critical for neuronal survival. Supplementation with nicotinamide (NAM), a precursor of NAD, can confer neuroprotective effects against glaucomatous damage caused by an age-related decline of NAD or mitochondrial dysfunction, reflecting the high metabolic activity of RGCs. However, oral supplementation of drug is relatively less efficient in terms of transmissibility to RGCs compared to direct delivery methods such as intraocular injection or delivery using subconjunctival depots. Neither method is ideal, given the risks of infection and subconjunctival scarring without novel techniques. By contrast, extracellular vesicles (EVs) have advantages as a drug delivery system with low immunogeneity and tissue interactions. We have evaluated the EV delivery of NAM as an RGC protective agent using a quantitative assessment of dendritic integrity using DiOlistics, which is confirmed to be a more sensitive measure of neuronal health in our mouse glaucoma model than the evaluation of somatic loss via the immunostaining method. NAM or NAM-loaded EVs showed a significant neuroprotective effect in the mouse retinal explant model. Furthermore, NAM-loaded EVs can penetrate the sclera once deployed in the subconjunctival space. These results confirm the feasibility of using subconjunctival injection of EVs to deliver NAM to intraocular targets.

Multiplexed PLGA scaffolds with nitric oxide-releasing zinc oxide and melatonin-modulated extracellular vesicles for severe chronic kidney disease.

INTRODUCTION: With prevalence of chronic kidney disease (CKD) in worldwide, the strategies to recover renal function via tissue regeneration could provide alternatives to kidney replacement therapies. However, due to relatively low reproducibility of renal basal cells and limited bioactivities of implanted biomaterials along with the high probability of substance-inducible inflammation and immunogenicity, kidney tissue regeneration could be challenging. OBJECTIVES: To exclude various side effects from cell transplantations, in this study, we have induced extracellular vesicles (EVs) incorporated cell-free hybrid PMEZ scaffolds. METHODS: Hybrid PMEZ scaffolds incorporating essential bioactive components, such as ricinoleic acid grafted Mg(OH)2 (M), extracellular matrix (E), and alpha lipoic acid-conjugated ZnO (Z) based on biodegradable porous PLGA (P) platform was successfully manufactured. Consecutively, for functional improvements, melatonin-modulated extracellular vesicles (mEVs), derived from the human umbilical cord MSCs in chemically defined media without serum impurities, were also loaded onto PMEZ scaffolds to construct the multiplexed PMEZ/mEV scaffold. RESULTS: With functionalities of Mg(OH)2 and extracellular matrix-loaded PLGA scaffolds, the continuous nitric oxide-releasing property of modified ZnO and remarkably upregulated regenerative functionalities of mEVs showed significantly enhanced kidney regenerative activities. Based on these, the structural and functional restoration has been practically achieved in 5/6 nephrectomy mouse models that mimicked severe human CKD. CONCLUSION: Our study has proved the combinatory bioactivities of the biodegradable PLGA-based multiplexed scaffold for kidney tissue regeneration in 5/6 nephrectomy mouse representing a severe CKD model. The optimal microenvironments for the morphogenetic formations of renal tissues and functional restorations have successfully achieved the combinatory bioactivities of remarkable components for PMEZ/mEV, which could be a promising therapeutic alternative for CKD treatment.