Bone Marrow Mesenchymal Stem Cell-Derived Small Extracellular Vesicles Promote Periodontal Regeneration

Abstract

Bone marrow mesenchymal stem cell-derived small extracellular vesicles (BMSC-sEVs) can be used as a potential cell-free strategy for periodontal tissue regeneration, and we aim to investigate the effect and possible mechanism of BMSC-sEV in periodontal tissue regeneration in this study. The BMSC-sEV was isolated by the Exosome Isola-tionÔ reagent and identified by transmission electron microscopy, nanoparticle tracking analysis, and Western blotting. The human periodontal ligament cells (hPDLCs) were cocultured with BMSC-sEV in vitro to detect the effects of BMSC-sEV on hPDLC migration, proliferation, and differentiation. The BMSC-sEV loaded by hydrogel was injected into experimental periodontitis rats to verify the therapeutic effect and possible mechanism. The results showed that BMSC-sEVs were 30-150 nm vesicles and expressed the exosome protein CD63 and tumor susceptibility 101 (TSG101), which could promote the migration, proliferation, osteogenic differentiation of hPDLCs. The BMSC-sEV-hydrogel had a therapeutic effect on periodontitis rats. After administration for 4-8 weeks, microcomputed tomography and histological analysis showed that alveolar bone loss, inflammatory infiltration, and collagen destruction in the BMSC-sEV-hydrogel group were less than that in the phosphate-buffered saline (PBS)hydrogel group and periodontitis group. Further immunohistochemical and immunofluorescent staining revealed that the number of tartrate-resistant acid phosphatase-positive cells and the expression ratio of osteoprotegerin (OPG) and receptor-activator of nuclear factor kappa beta ligand (RANKL) in the BMSC-sEV-hydrogel group were lower than that in the PBS-hydrogel group and periodontitis group, while the expression of transforming growth factor-beta 1 (TGF-b1) and the ratio of macrophage type 2 and macrophage type 1 (M2/M1) were opposite. Therefore, BMSC-sEV can promote the regeneration of periodontal tissues, and that may be partly due to BMSC-sEV involvement in the OPG-RANKL-RANK signaling pathway to regulate the function of osteoclasts and affect the macrophage polarization and TGF-b1 expression to modulate the inflammatory immune response, thereby inhibiting the development of periodontitis and immune damage of periodontal tissue.

Mesenchymal stem cell‐derived small extracellular vesicles as cell‐free therapy: Perspectives in periodontal regeneration

“…Only one study showed results at eight weeks, 48 the others did not go beyond four weeks. For the administration of sEV or conditioned medium, four studies use a collagen sponge, 18,31,35,40 one uses a resorbable collagen membrane, 39 two suspended sEV in phosphate‐buffered saline and inject locally into the periodontal pocket 13,23 and two use a hydrogel 34,48 . All these different delivery routes cannot guarantee equivalent concentrations of sEV in periodontal defects, which may explain the variable results observed.…”

“…However, there is some heterogeneity in the studies. Some use conditioned medium and others use sEV (called exosomes in four studies, sEV in one), most of which are derived from human cells and come from a variety of tissues (bone marrow MSC, 18,35,40,48 adipose MSC, 13 dental MSC 23,31,34,39 ). Two teams use rat MSC 13,48 .…”

“…Some use conditioned medium and others use sEV (called exosomes in four studies, sEV in one), most of which are derived from human cells and come from a variety of tissues (bone marrow MSC, 18,35,40,48 adipose MSC, 13 dental MSC 23,31,34,39 ). Two teams use rat MSC 13,48 . Six studies use a rat model of periodontitis, 13,18,31,35,39,48 two use the mouse model, 23,34 and one uses the dog model 40 .…”

“…Two teams use rat MSC 13,48 . Six studies use a rat model of periodontitis, 13,18,31,35,39,48 two use the mouse model, 23,34 and one uses the dog model 40 . Only one study showed results at eight weeks, 48 the others did not go beyond four weeks.…”

“…Six studies use a rat model of periodontitis, 13,18,31,35,39,48 two use the mouse model, 23,34 and one uses the dog model 40 . Only one study showed results at eight weeks, 48 the others did not go beyond four weeks. For the administration of sEV or conditioned medium, four studies use a collagen sponge, 18,31,35,40 one uses a resorbable collagen membrane, 39 two suspended sEV in phosphate‐buffered saline and inject locally into the periodontal pocket 13,23 and two use a hydrogel 34,48 .…”