MSC-derived sEVs enhance patency and inhibit calcification of synthetic vascular grafts by immunomodulation in a rat model of hyperlipidemia

Mesenchymal Stem Cell-Derived Extracellular Vesicles for Corneal Wound Repair

With the immunoregulation potential, mesenchymal stem cells (MSCs) have been used for tissue regeneration by relieving inflammation in the injured tissues. When this repair process is interfered by immune disorders or pathological angiogenesis, the delays in corneal epithelial wound healing can lead to a persistent epithelial defect. Stem cell-derived extracellular vesicles (EVs), which carry abundant bioactive molecules from stem cells, have provided an alternative to regeneration therapy. In this study, we aimed to investigate if EVs from human placenta-derived MSCs (hP-MSCs) could ameliorate alkali injury of the cornea in the mouse model. 33.33 μg/μL EVs in 10 μL PBS were applied to the cornea. Repeat application three times, and 100 μg EVs (in 30 μL PBS) in total were administrated per day for two weeks. Our results revealed that EVs from hP-MSCs had preferable functions including enhancing proliferation and anti-inflammation and suppressing apoptosis of corneal epithelial cells. Furthermore, hP-MSC-derived EVs ameliorated mouse corneal wound healing by inhibiting angiogenesis and inflammation. Taken together, our current data suggested that hP-MSC-derived EVs have the beneficial effects of corneal wound healing, which provide alternative cell-free therapy with great practical value.

Co-immobilization of ACH11 antithrombotic peptide and CAG cell-adhesive peptide onto vascular grafts for improved hemocompatibility and endothelialization

Surface modification by conjugating biomolecules has been widely proved to enhance biocompatibility of small-caliber artificial vascular grafts. In this study, we aimed at developing a multifunctional vascular graft that provides not only good hemocompatibility but also in situ rapid endothelialization. Herein, a vascular graft (inner diameter ∼2 mm) was fabricated by electrospinning with poly(lactic acid-co-caprolactone) and gelatin, and then biofunctionalized with antithrombotic peptide with sequence LTFPRIVFVLG (ACH₁₁) and cell adhesion peptide with sequence CAG through adhesive poly(dopamine) coating. We developed this graft with the synergistic properties of low thrombogenicity and rapid endothelialization. The successful grafting of both CAG and ACH₁₁ peptides was confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The surface micromorphology of the modified surfaces was observed by field emission scanning electron microscopy. Our results demonstrated that the multifunctional surface suppressed the denaturation of absorbed fibrinogen, hindered coagulation factor Xa activation, and inhibited platelet adhesion and aggregation. Importantly, this modified surface could selectively enhance endothelial cells adhesion, proliferation and release of nitric oxide. Upon in vivo implantation of 6 weeks, the multifunctional vascular graft showed improved patency and superior vascular endothelialization. Overall, the results effectively demonstrated that the co-immobilization of ACH₁₁ and CAG provided a promising method for the improvement of hemocompatibility and endothelialization of vascular grafts. STATEMENT OF SIGNIFICANCE: Electrospun small-caliber vascular grafts are increasingly used to treat cardiovascular diseases. Despite their success related to their good biodegradation and mechanical strength, they have some drawbacks, such as low hemocompatibility and endothelialization. The single-function ligands are insufficient to modify surface with both good hemocompatibility and rapid endothelialization simultaneously. Therefore, we functionalized electrospun vascular graft by novel antithrombotic peptide and cell-adhesive peptide to construct superior anticoagulation and ECs-selective adhesion surface in present study. The multifunctional vascular grafts benefit for high long-term patency and rapid endothelialization.