Exosomes from umbilical cord-derived mesenchymal stem cells combined with gelatin methacryloyl inhibit vein graft restenosis by enhancing endothelial functions

Stem cell therapy for intervertebral disc degeneration: Clinical progress with exosomes and gene vectors

Intervertebral disc degeneration is a leading cause of lower back pain and is characterized by pathological processes such as nucleus pulposus cell apoptosis, extracellular matrix imbalance, and annulus fibrosus rupture. These pathological changes result in disc height loss and functional decline, potentially leading to disc herniation. This comprehensive review aimed to address the current challenges in intervertebral disc degeneration treatment by evaluating the regenerative potential of stem cell-based therapies, with a particular focus on emerging technologies such as exosomes and gene vector systems. Through mechanisms such as differentiation, paracrine effects, and immunomodulation, stem cells facilitate extracellular matrix repair and reduce nucleus pulposus cell apoptosis. Despite recent advancements, clinical applications are hindered by challenges such as hypoxic disc environments and immune rejection. By analyzing recent preclinical and clinical findings, this review provided insights into optimizing stem cell therapy to overcome these obstacles and highlighted future directions in the field.

Nanomedicine-based strategies for the treatment of vein graft disease

Autologous saphenous veins are the most frequently used conduits for coronary and peripheral artery bypass grafting. However, vein graft failure rates of 40-50% within 10 years of the implantation lead to poor long-term outcomes after bypass surgery. Currently, only a few therapeutic approaches for vein graft disease have been successfully translated into clinical practice. Building on the past two decades of advanced understanding of vein graft biology and the pathophysiological mechanisms underlying vein graft disease, nanomedicine-based strategies offer promising opportunities to address this important unmet clinical need. In this Review, we provide deep insight into the latest developments in the rational design and applications of nanoparticles that have the potential to target specific cells during various pathophysiological stages of vein graft disease, including early endothelial dysfunction, intermediate intimal hyperplasia and late-stage accelerated atherosclerosis. Additionally, we underscore the convergence of nanofabricated biomaterials, with a particular focus on hydrogels, external graft support devices and cell-based therapies, alongside bypass surgery to improve local delivery efficiency and therapeutic efficacy. Finally, we provide a specific discussion on the considerations, challenges and novel perspectives for the future clinical translation of nanomedicine for the treatment of vein graft disease.

Stem Cells from Human Exfoliated Deciduous Teeth-Derived Exosomes for the Treatment of Acute Liver Injury and Liver Fibrosis

Mesenchymal stem cells (MSCs) play a crucial role in regenerative medicine due to their regenerative potential. However, traditional MSC-based therapies are hindered by issues such as microvascular obstruction and low cell survival after transplantation. Exosomes derived from MSCs (MSC-Exo) provide a cell-free, nanoscale alternative, mitigating these risks and offering therapeutic potential for liver diseases. Nonetheless, the functional variability of MSCs from different sources complicates their clinical application. Stem cells derived from human exfoliated deciduous teeth (SHED) offer advantages such as ease of procurement and robust proliferative capacity, but their secretome, particularly SHED-Exo, remains underexplored in the context of liver disease therapy. This study analyzed MSC-Exo from various sources via small RNA sequencing to identify differences in microRNA profiles, aiding in the selection of optimal MSC sources for clinical use. SHED-Exo was subsequently tested in an acute liver injury model, showing notable regenerative effects, including enhanced hepatocyte proliferation, macrophage polarization, and reduced inflammation. Despite strong liver-targeting properties, the rapid hepatic clearance of SHED-Exo limits its effectiveness in chronic liver diseases. To address this challenge, a GelMA-based hydrogel was developed for in situ delivery, ensuring sustained release and enhanced antifibrotic efficacy, providing a promising strategy for chronic liver disease management.

Extracellular Vesicles Delivered by a Nanofiber-Hydrogel Composite Enhance Healing In Vivo in a Model of Crohn's Disease Perianal Fistula

Perianal fistulas represent a common, aggressive, and disabling complication of Crohn's disease (CD). Despite recent drug developments, novel surgical interventions as well as multidisciplinary treatment approaches, the outcome is dismal, with >50% therapy failure rates. Extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) offer potential therapeutic benefits for treating fistulizing CD, due to the pro-regenerative paracrine signals. However, a significant obstacle to clinical translation of EV-based therapy is the rapid clearance and short half-life of EVs in vivo. Here, an injectable, biodegradable nanofiber-hydrogel composite (NHC) microgel matrix that serves as a carrier to deliver MSC-derived EVs to a rat model of CD perianal fistula (PAF) is reported. It is found that EV-loaded NHC (EV-NHC) yields the best fistula healing when compared to other treatment arms. The MRI assessment reveals that the EV-NHC reduces inflammation at the fistula site and promotes tissue healing. The enhanced therapeutic outcomes are contributed by extended local retention and sustained release of EVs by NHC. In addition, the EV-NHC effectively reduces inflammation at the fistula site and promotes tissue healing and regeneration via macrophage polarization and neo-vascularization. This EV-NHC platform provides an off-the-shelf solution that facilitates its clinical translation.

Small Extracellular Vesicles and Oral Mucosa: The Power Couple in Regenerative Therapies?

Although ongoing debates persist over the scope of phenomena classified as regenerative processes, the most up-to-date definition of regeneration is the replacement or restoration of damaged or missing cells, tissues, organs, or body parts to full functionality. Despite extensive research on this topic, new methods in regenerative medicine are continually sought, and existing ones are being improved. Small extracellular vesicles (sEVs) have gained attention for their regenerative potential, as evidenced by existing studies conducted by independent research groups. Of particular interest are sEVs derived from the oral mucosa, a tissue renowned for its rapid regeneration and minimal scarring. While the individual regenerative potential of both sEVs and the oral mucosa is somewhat understood, the combined potential of sEVs derived from the oral mucosa has not been sufficiently explored and highlighted in the existing literature. Serving as a broad compendium, it aims to provide scientists with essential and detailed information on this subject, including the nature of the materials employed, isolation and analysis methodologies, and clinical applications. The content of this survey aims to facilitate the comparison of diverse methods for working with sEVs derived from the oral mucosa, aiding in the planning of research endeavors and identifying potential research gaps.

Application of mesenchymal stem cells derived from the umbilical cord or Wharton's jelly and their extracellular vesicles in the treatment of various diseases

Mesenchymal stem cells (MSCs) originating from the umbilical cord (UC) or Wharton's jelly (WJ) have attracted substantial interest due to their potential to augment therapeutic approaches for a wide range of disorders. These cells demonstrate a wide range of capabilities in the process of differentiating into a multitude of cell types. Additionally, they possess a significant capacity for proliferation and are conveniently accessible. Furthermore, they possess a status of being immune-privileged, exhibit minimal tumorigenic characteristics, and raise minimal ethical concerns. Consequently, they are well-suited candidates for tissue regeneration and the treatment of diseases. Additionally, UC-derived MSCs offer a substantial yield compared to other sources. The therapeutic effects of these MSCs are closely associated with the release of nanosized extracellular vesicles (EVs), including exosomes and microvesicles (MVs), containing lipids, microRNAs, and proteins that facilitate intercellular communication. Due to their reduced tumorigenic and immunogenic characteristics, in addition to their convenient manipulability, EVs have arisen as a viable alternative for the management of disorders. The favorable characteristics of UC-MSCs or WJ-MSCs and their EVs have generated significant attention in clinical investigations encompassing diverse pathologies. Therefore, we present a review encompassing current preclinical and clinical investigations, examining the implications of UC-MSCs in diverse diseases, including those affecting bone, cartilage, skin, liver, kidney, neural, lung, cardiovascular, muscle, and retinal tissues, as well as conditions like cancer, diabetes, sepsis, and others.

Functional extracellular vesicles from SHEDs combined with gelatin methacryloyl promote the odontogenic differentiation of DPSCs for pulp regeneration

BACKGROUND

Pulp regeneration is a novel approach for the treatment of immature permanent teeth with pulp necrosis. This technique includes the combination of stem cells, scaffolds, and growth factors. Recently, stem cell-derived extracellular vesicles (EVs) have emerged as a new methodology for pulp regeneration. Emerging evidence has proven that preconditioning is an effective scheme to modify EVs for better therapeutic potency. Meanwhile, proper scaffolding is of great significance to protect EVs from rapid clearance and destruction. This investigation aims to fabricate an injectable hydrogel loaded with EVs from pre-differentiated stem cells from human exfoliated deciduous teeth (SHEDs) and examine their effects on pulp regeneration.

RESULTS

We successfully employed the odontogenic induction medium (OM) of SHEDs to generate functional EV (OM-EV). The OM-EV at a concentration of 20 µg/mL was demonstrated to promote the proliferation and migration of dental pulp stem cells (DPSCs). The results revealed that OM-EV has a better potential to promote odontogenic differentiation of DPSCs than common EVs (CM-EV) in vitro through Alizarin red phalloidin, alkaline phosphatase staining, and assessment of the expression of odontogenic-related markers. High-throughput sequencing suggests that the superior effects of OM-EV may be attributed to activation of the AMPK/mTOR pathway. Simultaneously, we prepared a photocrosslinkable gelatin methacryloyl (GelMA) to construct an OM-EV-encapsulated hydrogel. The hydrogel exhibited sustained release of OM-EV and good biocompatibility for DPSCs. The released OM-EV from the hydrogel could be internalized by DPSCs, thereby enhancing their survival and migration. In tooth root slices that were subcutaneously transplanted in nude mice, the OM-EV-encapsulated hydrogel was found to facilitate dentinogenesis. After 8 weeks, there was more formation of mineralized tissue, as well as higher levels of dentin sialophosphoprotein (DSPP) and dentin matrix protein-1 (DMP-1).

CONCLUSIONS

The effects of EV can be substantially enhanced by preconditioning of SHEDs. The functional EVs from SHEDs combined with GelMA are capable of effectively promoting dentinogenesis through upregulating the odontogenic differentiation of DPSCs, which provides a promising therapeutic approach for pulp regeneration.

Tailored gelatin methacryloyl-based hydrogel with near-infrared responsive delivery of Qiai essential oils boosting reactive oxygen species scavenging, antimicrobial, and anti-inflammatory activities for diabetic wound healing

The management of diabetic wounds poses a substantial economic and medical burden for diabetic patients. Oxidative stress and persistent bacterial infections are considered to be the primary factors. Qiai essential oil (QEO) exhibits various pharmacological characteristics, including inflammatory-reducing, antibacterial, and antioxidant properties. Nevertheless, the hydrophobic nature and propensity for explosive release of this substance present constraints on its potential for future applications. Here, we developed a stimulus-responsive hydrogel to overcome the multiple limitations of QEO-based wound dressings. The QEO was encapsulated within graphene oxide (GO) through repeated extrusion using an extruder. Subsequently, QEO@GO nanoparticles were incorporated into a Gelatin-methacryloyl (GelMA) hydrogel. The QEO@GO-GelMA hydrogel demonstrated controlled release ablation, photothermal antibacterial effects, and contact ablation against two representative bacterial strains. It effectively reduced reactive oxygen species (ROS) generation, promoted angiogenesis, and decreased levels of the pro-inflammatory cytokine interleukin-6 (IL-6), thereby accelerating the healing process of diabetic wounds. In addition, in vitro and in vivo tests provided further evidence of the favorable biocompatibility of this multifunctional hydrogel dressing. Overall, the QEO@GO-GelMA hydrogel provides numerous benefits, encompassing antimicrobial properties, ROS-scavenging abilities, anti-inflammatory effects, and the capacity to expedite diabetic wound healing. These attributes make it an optimal choice for diabetic wound management.