Table 1.
Studies of BM-MSC derived EVs for promoting bone regeneration.
| EV cell origin |
EV size (nm) | Content profile |
In vitro effects |
In vivo |
Pathway(s) involved | Ref | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Species | Passage | Markers | miRNA | Model | Delivery mechanism | Amount of EV delivered | In vivo effects | ||||
| Human | 3rd to 5th | Not mentioned | CD63 | 196a, 27a, 206 | Internalized into the endoplasmic reticulum, Golgi apparatus and lysosomes of human osteoblasts. Marginal increase in proliferation. Increased ALP, OCN, OPN & RUNX2 expression | 5 mm rat calvarial defect | Hystem®-Heparin hydrogel | 100 μg | 8 wk- Significantly increased amount and area density of newly formed bone in the EV group as compared to hydrogel and blank control | Not mentioned | (Qin et al., 2016) |
| Human | 3rd to 6th | 80-100 | CD9, CD63, CD81 | Not mentioned | Increased proliferation, mineral deposition, and expression levels of COL1, ALP, OCN, OPN, VEGF, ANG1&2 in MSCs | 5 mm rat calvarial defect | Atelocollagen sponges | 30 μg | 4 wk- Increased area of newly formed bone in the MSC-EV group than in the MSC-CM group. More cells stained for OCN, VEGF, CD31 and CD44 | Not mentioned | (Takeuchi et al., 2019) |
| Human | 4th to 6th | ~80 | CD9, CD81 and flotillin1 | miR-4532, miR-125b-5p, miR-338-3p, miR-548aa. | None | Murine femoral fracture | Local injection | 100 μl | 2 wk- Accelerated formation of hypertrophic chondrocytes, more woven bone and improved fracture healing, many TRAP+ cells in callus of EV injected group. | MCP-1, MCP-3, SDF-1 and VEGF (although effects not solely attributable to these factors) | (Furuta et al., 2016) |
| Human | 4th | ~100 | CD63 | Not mentioned | Increased expression of ALP, OSX, RUNX2 and ARS staining in iliac BM-MSCs incubated with EVs from maxillary BM-MSCs | 4 mm murine (nude) calvarial defect | PLGA scaffold | Not mentioned | 12 wk- More new bone formation in group implanted with iliac BM-MSC treated with maxillary BM-MSC EVs than group implanted with iliac BM-MSC treated with iliac BM-MSC EVs | siRNA: Rab26a | (Li et al., 2019) |
| Human | 4th–6th | 50-150 | CD9, CD63, Hsp70 | MALAT1, miR-34c | Increased osteoblast proliferation, ALP activity and calcium nodule formation | Mouse OVX model | Periostial injection | 20 μl | 3wk- Bone formation rate increased in mice injected with oe-MALAT1 and decreased in mice injected with miR-34c agomir and sh-SATB2. | miRNA-34c/SATB2 axis | (Yang et al., 2019) |
| Human (specific source of MSC not mentioned) | Not mentioned | 100-200 | CD81, Alix, TSG101 | Not mentioned | Enhanced PLSCs proliferation and migration | Rat periodontal defect | Collagen sponges | 40 μg | 4wk- increased bone formation, aligned PDL fibers, and closure of bone gap compared to collagen group | AKT and ERK pathways in PLSCs | (Chew et al., 2019) |
| Rat | 3rd to 4th | 100-1000 | CD73, 105, 29, 44, 90, 34, 45 | Not mentioned | Dose-dependent increase in growth in HUVECs. Increased HUVEC migration and tube formation. No effect on MSC proliferation, apoptosis and differentiation. | Nude mice SQ implantation | DBM scaffold coated with fibronectin | 20 μg | 1&2 m- Increased BV and BV/TV in cells + EV scaffold, more bone regeneration and osteoblast like cells. More CD31 labeling in cells + EV group | Not mentioned | (Xie et al., 2017) |
| Rat | 2nd-5th | 122 | CD9, CD63, CD81 | Not mentioned | Promoted proliferation and migration of HUVECs and MC3T3 cells. Promoted tube formation in HUVECs and osteogenic differentiation of MC3T3s | Rat femoral fracture | Injected at fracture site | 1010 | 20wk- Significantly increased callus formation, BV/TV, vascular branching, and expression of CD31, VEGF, HIF-1α, BMP2, Smad1/5, RUNX2, OGN, OPN and OCN in EV group compared to control | BMP2/Smad1/RUNX2 signaling pathway | (Zhang et al., 2020) |
| Rat | 3rd-4th | 100-1000 | CD73, CD105, CD29, CD44, and CD90 | Not mentioned | Promoted tube formation of HUVECs | SQ Nude mice | PCL-alginate scaffold | 1 μg/μl | 8wk- Increased bone and blood vessel formation in cell+EV+ Scaffold group as compared to cell + Scaffold, EV + Scaffold or scaffold groups | Not mentioned | (Xie et al., 2016) |
| Rat (young-4wk vs old-72wk) | 3rd-5th | 50-150 | CD63, CD81 | miR-128-3p in old EVs | Young EVs induced higher expression of RUNX2, ALP and COL1 in BM-MSCs than old EVs | Rat femoral fracture | Injection at fracture site | 200 μg | 2wk- young EVs stimulated more callus formation in fracture gap with increased expression of RUNX2, ALP and COL1 as compared to old EVs | Not mentioned | (Xu et al., 2020) |
| Rat (2wk old) |
3rd-5th | 60-130 | CD9, CD63, TSG101 | Not mentioned | Increased proliferation, calcium deposition and expression of ALP, RUNX2, and OCN in old MSCs | Old Rat (60wk) tibial DO | Injection at distraction site | 1 × 1010 | 5wk- Increased BV/TV, BMD, ultimate load, and energy to failure in EV group than control group. | Not mentioned | (Jia et al., 2020) |
| Mouse | Not mentioned | 35-105 | CD63, CD81, TSG101 | miR-26a | Increased internalization by BM-MSCs and RAW264.7 cells after aptamer functionalization. Dose-dependent increase in OCN, RUNX2 & ALP levels and matrix mineralization. Did not affect osteoclastic differentiation of RAW264.7 cells. | OVX murine femoral fracture | Tail vein injection | 100 μg | OVX only model: 8 wk. – Significant increase in trabecular number, thickness, and volume and OCN stained area in aptamer EV group with no effect on osteoclastic differentiation. Fracture model: 6 wk- Increased width and area of callus and increased BV/TV in the aptamer EV group. |
Not mentioned | (Luo et al., 2019) |
| Mouse | Not mentioned | 170.3 ± 8.6 | CD9, CD29, CD44, CD90 and Sca-1 | Let-7a | EVs promoted chondrocyte proliferation | G610C OI mice | Tail vein injection | Not mentioned | 2wk - longer femora and tibiae in EV group than control group | Not mentioned | (Otsuru et al., 2018) |
BM-MSC: Bone marrow mesenchymal stromal cells; OCN: Osteocalcin; RUNX: Runt-related transcription factor; ALP: Alkaline phosphatase; OPN: Osteopontin; COL: Collagen; EV: Extracellular vesicle; CM: Conditioned medium; VEGF: Vascular endothelial growth factor; ANG: Angiopoietin; OVX: Ovariectomized; BV/TV: Bone volume/total volume; HUVEC: Human umbilical vein endothelial cells; BMP: Bone Morphogenetic Protein; SQ: subcutaneous; TRAP: Tartrate-resistant acid phosphatase; OSX: Osterix; ARS: Alizarin red S; PLGA: Poly lactic- co-glycolic acid; DBM: Demineralized bone matrix; BMD: Bone mineral density; DO: Distraction osteogenesis; PLSCs: Periodontal ligament stem cells; MCP: Monocyte chemotactic protein; SDF: Stromal cell-derived factor; MALAT: Metastasis associated lung adenocarcinoma transcript; SATB: Special AT-rich sequence-binding protein; PDL: Periodontal ligament; AKT: Protein kinase B; ERK: Extracellular receptor kinase; HIF: Hypoxia inducible factor; PCL: Poly caprolactone; OGN: Osteoglycin.