Extracellular vesicles from adipose-derived stem cells in bone regeneration: Mechanisms and therapeutic advances

Table 1 Preclinical strategies of adipose-derived stem cell-derived extracellular vesicles in bone defect

Pretreated cells/modified EVs	Strategy	In vivo model	Delivery route	In vivo effects	Ref.
Osteogenically induced ADSC-EVs	PLGA/PDA scaffold for sustained release	Mouse (4 mm defect)	Scaffold implantation	↑Bone volume, collagen, RUNX2/OCN expression; ↑BMSC osteogenesis	[21]
ADSC-EVs enriched with miR-375 (genetically modified ADSCs)	MiR-375 overexpression targeting IGFBP3	Rat (5 mm defect)	Hydrogel implantation	↑BV/TV, BMD, new bone	[26]
CREKA-modified rat ADSC-EVs	CREKA peptide for fibrin targeting	Rat femoral condyle (2.8 mm × 3 mm)	Local injection (40 μL)	↑BV/TV, Tb.Th, OCN, CD31; ↑M2 macrophages; ↓inflammation	[28]
Biotinylated ADSC-EVs	Avidin-biotin complex system on Bio-Ppy-Ti surface	Subcutaneous ectopic model	Immobilization on Ti (not injected)	↑ALP, COL I, OCN; ↑osseointegration	[29]
ADSC-EVs (unmodified)	PDA-coated gelatin sponge scaffold	Rat femoral condyle (3 mm defect)	Scaffold implantation	↑New bone, BMD, BV/TV, osteogenic markers; ↓Tb.Sp	[30]
ADSC-EVs (unmodified)	3D-bioprinted bilayer dECM hydrogel	Rat knee joint (4 mm defect)	Bilayer hydrogel implantation	↑Cartilage/subchondral bone repair, biomechanics; ↓IL-1β	[31]
ADSC-EVs (unmodified)	Injectable GNP hydrogel via miR-451a/MIF	Rat (5 mm defect)	Hydrogel injection	↑Bone healing, BV/TV, Tb.N/Th; ↑M2 polarization	[32]
ADSC-EVs (unmodified)	PLGA/Mg-GA MOF scaffold	Rat (6.5 mm defect)	Scaffold implantation	↑BV/TV, BMD, angiogenesis, osteogenesis; ↓inflammation	[33]
ADSC-EVs (unmodified)	None	STZ-induced T2DM rat femoral fracture	Local injection (600 μL, 200 μg/mL, every 3 days)	↑Mineralization, callus formation, BV/TV, and fracture healing	[40]

EVs: Extracellular vesicles; ADSC-EVs: Adipose-derived stem cell-derived extracellular vesicles; PLGA: Poly(lactic-co-glycolic acid); PDA: Polydopamine; RUNX2: Runt-related transcription factor 2; OCN: Osteocalcin; BMSC: Bone marrow mesenchymal stem cells; miR-375: MicroRNA-375; ADSC: Adipose-derived stem cell; IGFBP3: Insulin-like growth factor binding protein 3; BV/TV: Bone volume/total volume; BMD: Bone mineral density; CREKA: Cys-Arg-Glu-Lys-Ala; Tb.Th: Trabecular thickness; CD31: Cluster of differentiation 31; ALP: Alkaline phosphatase; COL I: Collagen type I; Ppy: Polypyrrole; Ti: Titanium; Tb.Sp: Trabecular separation; dECM: Decellularized extracellular matrix; IL-1β: Interleukin-1β; GNP: Gelatin-nanoparticle; miR-451a: MicroRNA-451a; MIF: Migration inhibitory factor; Tb.N: Trabecular number; Mg-GA MOF: Magnesium-gallic acid metal-organic framework; STZ: Streptozotocin; T2DM: Type 2 diabetes mellitus.

Table 2 Preclinical Strategies of adipose-derived stem cell-derived extracellular vesicles in osteoarthritis

Pretreated cells/modified EVs	Strategy	In vivo model	Delivery route	Effects in vivo	Ref.
ADSCs stimulated with ↓TNF-α & IFN-γ to ADSC-EVs	MiR-27b-3p enriched EVs + SF scaffold	Rabbit TMJ condylar defect	Scaffold implantation	↑BMSC proliferation, osteo-/chondrogenesis; ↑M2 macrophages; ↓inflammation; ↑bone/cartilage repair	[22]
PEMF-stimulated rat ADSC-EVs	PEMF stimulation (15-75 Hz) to enhance EVs	ACLT rat OA model	IA injection (40 μL, weekly × 4)	↑Anabolic cartilage markers; ↓MMP-13, IL-1β; ↑histology scores; ↓inflammation	[23]
ADSC-EVs enriched with miR-486-5p (miR-486-5p mimic-transfected ADSCs)	Engineered EVs delivering miR-486-5p	DMM rat OA model	IA injection (20 μL, weekly × 10)	↓Chondrocyte apoptosis, MMP-13, inflammation; ↑COL II, cartilage matrix; ↓OARSI score	[24]
Curcumin-loaded ADSC-EVs	Drug-loading to enhance antioxidant & anti-apoptosis	ACLT mouse model	IA injection (10 μL, biweekly × 4)	↓Cartilage degeneration, oxidative stress, apoptosis, pain; ↑ECM components (COL II, aggrecan)	[27]
ADSC-EVs enriched with miR-376c-3p	MiR-376c-3p delivery targeting WNT/β-catenin	MIA rat OA model	IA injection (100 μg EVs, single dose)	↓Cartilage degradation, fibrosis, inflammatory cytokines; ↑COL II; WNT signaling inhibition	[90]
ADSC-EVs (unmodified)	Native EVs isolated by TFF	MIA-induced rat OA model	IA injection (30 μL, weekly × 3 or 6)	↓Mankin score, cartilage erosion, inflammatory markers; ↑cartilage matrix protection	[91]
ADSC-EVs (unmodified)	Native EVs isolated by TFF	DMM mouse OA model	IA injection (6 μL, weekly × 6)	↓OARSI score, synovial inflammation, M1 macrophages; ↑COL II, chondrocyte proliferation/migration	[91]

EVs: Extracellular vesicles; ADSC: Adipose-derived stem cell; TNF-α: Tumor necrosis factor-alpha; IFN-γ: Interferon-gamma; ADSC-EVs: Adipose-derived stem cell-derived extracellular vesicles; miR-27b-3p: MicroRNA-27b-3p; SF: Silk fibroin; TMJ: Temporomandibular joint; BMSC: Bone marrow mesenchymal stem cells; PEMF: Pulsed electromagnetic field; ACLT: Anterior cruciate ligament transection; OA: Osteoarthritis; IA: Intra-articular; MMP-13: Matrix metalloproteinase-13; IL-1β: Interleukin-1β; miR-486-5p: MicroRNA-486-5p; DMM: Destabilization of the medial meniscus; COL II: Collagen type II; OARSI: Osteoarthritis Research Society International; ECM: Extracellular matrix; miR-376c-3p: MicroRNA-376c-3p; MIA: Monosodium iodoacetate; TFF: Tangential flow filtration.

Table 3 Preclinical strategies of adipose-derived stem cell-derived extracellular vesicles in osteoporosis

Pretreated cells/modified EVs	Mechanism	Animal model	Delivery	In vivo effects	Ref.
MiR-146a-overexpressing ADSC-EVs	MiR-146a delivery to suppress inflammasome	STZ-induced diabetic rat	Tail vein, every 2 days	↑Bone density; ↓inflammation; best effect with miR-146a	[25]
ADSC-EVs (unmodified)	Activates Nrf2/HO-1	Dexamethasone rat	Tail vein, 3 ×/week	↑BMD, BV/TV, Tb.Th, Tb.N; ↓apoptosis; ↑osteogenesis	[83]
ADSC-EVs enriched in OPG, miR-21-5p	Inhibit osteoclastogenesis; promote MSC migration	OVX mouse	IV, 3 ×/week	↑BMD, BV/TV, Tb.Th, Tb.N; ↓osteoclasts; ↑MSC migration	[85]
WSTLZT-treated ADSC-EVs (miR-122-5p)	Regulate bone-fat balance via SPRY2/MAPK	OVX mouse	Tail vein, weekly	↑BMD, BV/TV, Tb.Th; ↓Tb.Sp, marrow adipose; ↑osteogenesis	[94]
ADSC-EVs (unmodified)	Suppress NLRP3 inflammasome	STZ-induced diabetic rat	Tail vein, every 2 days	↑Bone mineral density; ↓IL-1β, IL-18; ↓osteoclasts	[95]

EVs: Extracellular vesicles; miR-146a: MicroRNA-146a; ADSC-EVs: Adipose-derived stem cell-derived extracellular vesicles; STZ: Streptozotocin; Nrf2: Nuclear factor-E2-related factor 2; HO-1: Heme oxygenase-1; BMD: Bone mineral density; BV/TV: Bone volume/total volume; Tb.Th: Trabecular thickness; Tb.N: Trabecular number; OPG: Osteoprotegerin; miR-21-5p: MicroRNA-21-5p; MSC: Mesenchymal stem cell; OVX: Ovariectomized; IV: Intravenous; WSTLZT: Wen-Shen-Tong-Luo-Zhi-Tong; miR-122-5p: MicroRNA-122-5p; SPRY2: Sprouty homolog 2; MAPK: Mitogen-activated protein kinase; Tb.Sp: Trabecular separation; NLRP3: NOD-like receptor pyrin domain-containing protein 3; IL-1β: Interleukin-1β; IL-18: Interleukin-18.