Multibiofunctional TFEB-engineered endothelial progenitor cell-derived extracellular vesicles/hydrogel system for rescuing critical limb ischemia

Biomaterial-based vascularization strategies for enhanced treatment of peripheral arterial disease

Peripheral arterial disease (PAD) poses a global health challenge, particularly in its advanced stages known as critical limb ischemia (CLI). Conventional treatments often fail to achieve satisfactory outcomes. Patients with CLI face high rates of morbidity and mortality, underscoring the urgent need for innovative therapeutic strategies. Recent advancements in biomaterials and biotechnology have positioned biomaterial-based vascularization strategies as promising approaches to improve blood perfusion and ameliorate ischemic conditions in affected tissues. These materials have shown potential to enhance therapeutic outcomes while mitigating toxicity concerns. This work summarizes the current status of PAD and highlights emerging biomaterial-based strategies for its treatment, focusing on functional genes, cells, proteins, and metal ions, as well as their delivery and controlled release systems. Additionally, the limitations associated with these approaches are discussed. This review provides a framework for designing therapeutic biomaterials and offers insights into their potential for clinical translation, contributing to the advancement of PAD treatments.

Engineering small extracellular vesicles with multivalent DNA probes for precise tumor targeting and enhanced synergistic therapy

Small extracellular vesicles (sEVs) have gained wide attention as efficient carriers for disease treatment. However, the proclivity of sEVs to be ingested by source cells is insufficient to accurately target specific sites, posing a challenge in realizing controlled targeting treatment. Here, we developed an engineered sEV nanocarrier capable of precise tumor targeting and enhanced synergistic therapy. Multivalent DNA probes, comprising abundant AS1411 aptamers and telomerase primers, were innovatively modified on the sEV membrane (M-D-sEV) for precise tumor targeting. To achieve synergistic therapy, gold nanorod-cerium oxide nanostructures (Au NRs-CeO2) and manganese dioxide nanosheets-doxorubicin (MnO2 NSs-DOX) were encapsulated into liposomes (Lip-Mat). Then M-D-sEV and Lip-Mat were fused together through membrane fusion to obtain nanocarriers. Owing to the multivalence of the probes, the surface of the nanocarriers was loaded with numerous aptamers, which greatly enhances their targeting ability and promotes the accumulation of drugs. When nanocarriers were ingested by tumor cells, telomerase and multivalent DNA probes triggered their aggregation, enhancing the therapeutic effect. Furthermore, under laser irradiation, Au NRs-CeO2 converted light into hyperthermia, thereby inducing the destruction of nanocarriers membrane. This process initiated a series of reactions involving glutathione and H2O2 consumption, as well as DOX release, ultimately achieving synergistic tumor therapy. In vitro and in vivo studies demonstrated the remarkable targeting ability of multivalent DNA probes and excellent therapeutic effect of this strategy. The engineered strategy of sEVs provide a promising approach for precise tumor therapy and hold great potential for the development of efficient, safe, and personalized drug delivery systems.

Emerging Strategies for Revascularization: Use of Cell-Derived Extracellular Vesicles and Artificial Nanovesicles in Critical Limb Ischemia

Critical limb ischemia (CLI) poses a substantial and intricate challenge in vascular medicine, necessitating the development of innovative therapeutic strategies to address its multifaceted pathophysiology. Conventional revascularization approaches often fail to adequately address the complexity of CLI, necessitating the identification of alternative methodologies. This review explores uncharted territory beyond traditional therapies, focusing on the potential of two distinct yet interrelated entities: cell-derived extracellular vesicles (EVs) and artificial nanovesicles. Cell-derived EVs are small membranous structures naturally released by cells, and artificial nanovesicles are artificially engineered nanosized vesicles. Both these vesicles represent promising avenues for therapeutic intervention. They act as carriers of bioactive cargo, including proteins, nucleic acids, and lipids, that can modulate intricate cellular responses associated with ischemic tissue repair and angiogenesis. This review also assesses the evolving landscape of CLI revascularization through the unique perspective of cell-derived EVs and artificial nanovesicles. The review spans the spectrum from early preclinical investigations to the latest translational advancements, providing a comprehensive overview of the current state of research in this emerging field. These groundbreaking vesicle therapies hold immense potential for revolutionizing CLI treatment paradigms.

Polylactic acid/chitosan-IKVAV Janus film serving as a dual functional platform for spinal cord injury repair

The repair of traumatic spinal cord injury (SCI) remains a challenge due to the non-regenerative nature of functional neurons in adults. Neural stem cell (NSC)-based therapy has emerged as a promising approach for the treatment of SCI by replacing the damaged neurons with differentiated stem cells. However, directing the neuronal differentiation of implanted stem cells in the injury microenvironment is of great difficulty, especially considering that SCI is generally associated with severe fibrotic tissue infiltration, neuron inflammation, and tissue adhesion. Here, we propose a dual functional Janus film capable of preventing tissue adhesion and promoting the neuronal differentiation of stem cells for the treatment of SCI. The Janus film is composed of a layer of polylactic acid (PLA) and a layer of chitosan (CS) grafted with IKVAV peptides. The PLA layer prevents the invasion of the fibrotic tissue, while the IKVAV peptide-grafted CS layer offers support for NSC implantation and thus the neuronal differentiation of the NSCs. When serving as the dura patch, the Janus films seeded with NSCs promote the recovery of motor function and the regeneration of the injured spinal cord tissue of SCI rats. This dual functional Janus film holds great promise for treating SCI in combination with stem cell therapy.

Injectable Alginate-Based Hydrogels Encapsulating Engineered Endothelial Extracellular Vesicles for the Treatment of Critical Limb Ischemia

Critical limb ischemia (CLI) is a peripheral arterial disease resulting from chronic inflammation of vascular systems. Recent studies have shown that inhibiting macrophage inflammation has the potential to treat CLI, and extracellular vesicles (EVs) from endothelial cells can inhibit macrophage activation. However, the limited cell-targeting capabilities and rapid clearance of EVs from the injection site limit the in vivo application of the EVs. Here, we modified endothelial EVs with platelet membranes (pM/EVs) to boost the inhibition effects on macrophage inflammation and developed an injectable alginate-based collagen composite (ACC) hydrogel for localized delivery of pM/EVs (pM/EVs@ACC) for CLI treatment. We found that pM/EVs can effectively inhibit macrophage inflammation in vitro. Furthermore, pM/EVs@ACC treatment significantly promotes the recovery of limb functions, restoring the feet' blood supply and relieving inflammation. Our findings provide compelling evidence that the pM/EVs@ACC injectable system mediating delivery of pM/EVs is a promising strategy for CLI treatment.

Poly(ethylenimine)-Cyclodextrin-Based Cationic Polymer Mediated HIF-1α Gene Delivery for Hindlimb Ischemia Treatment

Hindlimb ischemia is a common disease worldwide featured by the sudden decrease in limb perfusion, which usually causes a potential threat to limb viability and even amputation or death. Revascularization has been defined as the gold-standard therapy for hindlimb ischemia. Considering that vascular injury recovery requires cellular adaptation to the hypoxia, hypoxia-inducible factor 1 α (HIF-1α) is a potential gene for tissue restoration and angiogenesis. In this manuscript, effective gene delivery vector PEI-β-CD (PC) was reported for the first application in the hindlimb ischemia treatment to deliver HIF-1α plasmid in vitro and in vivo. Our in vitro finding demonstrated that PC/HIF-1α-pDNA could be successfully entered into the cells and mediated efficient gene transfection with good biocompatibility. More importantly, under hypoxic conditions, PC/HIF-1α-pDNA could up-regulate the HUEVC cell viability. In addition, the mRNA levels of VEGF, Ang-1, and PDGF were upregulated, and transcriptome results also demonstrated that the cell-related function of response to hypoxia was enhanced. The therapeutic effect of PC/HIF-1α-pDNA was further estimated in a murine acute hindlimb ischemia model, which demonstrated that intramuscular injection of PC/HIF-1α-pDNA resulted in significantly increased blood perfusion and alleviation in tissue damage, such as tissue fibrosis and inflammation. The results provide a rationale that HIF-1α-mediated gene therapy might be a practical strategy for the treatment of limb ischemia.