Table 2.

The characteristics and values of EVs in the diagnosis of OA.

Sources		Characteristic	Diagnosis value	Relationship with OA	Ref.
Blood	Plasma	Lower expression of miR-193b	Early diagnosis;	miR-193b is negatively correlated with inflammation	[44]
			Reflect the phenotypes
	Serum	Higher expression of cathepsin F and lower lg α2 chain C	Early diagnosis	Cathepsin F may involve in the pathogenesis of OA	[122]
	Plasma	Ratios of neutrophil-EVs to lymphocyte-EVs were positively correlated between plasma and SF	Early diagnosis;	Reflect OA joint inflammation and disease severity	[124]
			Reflect the severity of OA
synovial fluid	Synovial fluid	Higher expression of HLA-DR,-DP, and -DQ	Reflect the severity of OA	Mainly originated from the immune cell infiltration in the OA joint	[124]
	Synovial fluid	Higher expression of PCGEM1 in late OA than in early OA	Reflect the stages of OA	PCGEM1 inhibited apoptosis, induced autophagy, and stimulated proliferation	[123,125]
	Synovial fluid	Differential expression of miRNA between men and women	Reflect the subtype of OA	female specific miRNAs are estrogen responsive and target TLR signaling pathways.	[120]
	Synovial fluid	Differential expression of miRNA before and after treatment	Evaluate the effect of treatment	Correlated with cartilage production (in young mice) and immune (in aged mice)	[48]
Tissue biopsies	Synovial fibroblasts	Differential expression of fifty miRNAs	Reflect the susceptibility of OA	miRNA expression patterns in exosomes are altered and miRNAs are selectively released;	[37]
	Chondrocytes	Nine proteins only present in OA-ACVs	Reflect the presence of stromal changes and predict OA	Differences in ECM proteins in OA and normal ACVs largely reflect known changes in OA ECM and increased catabolism	[126]

*ACV: articular cartilage vesicles.