Table 1 Summary of the preparation of adipose cell-free derivatives

ADSC-CM

1. Add ADSC to basal medium containing 10% fetal bovine serum for cultivation

2. When ADSC reaches 70–80% confluence, change the basic medium to serum-free medium

3. After cultivating for 48–72 h, collect the medium and centrifuge at 1000 g × 5 min,

4. Filter with a 0.22-μm syringe

Rich in cytokines, but enzyme digestion and in vitro cultivation are required during the preparation process, increasing the risk of biological contamination

bFGF [15, 16]; EGF [15];

PDGF-AA [15, 17]; VEGF [15]

KGF [16]; TGF-β [16]; HGF [16, 18], IGF-1 [44]; BDNF [19]

ADSC-Exo

1. Add ADSC to basal medium containing 10% fetal bovine serum for cultivation

2. When ADSC reaches 70–80% confluence, change the basic medium to serum-free medium

3. After 48 h incubation, collect the supernatant and centrifuge

4. To remove any cells and cellular debris, the medium is centrifuged at 300 g for 10 min, 2000 g for 10 min and 10,000 g for 30 min

5. Then, the medium is ultracentrifuged at 100,000 g for 70 min.

6. Finally, Exos at the bottom of the centrifuge tube are resuspended in PBS and centrifuged at 100,000 g for 70 min to eliminate contaminating proteins

In addition to cytokines, it is also rich in signaling molecules such as protein, mRNA, and miRNA, but the preparation steps are complicated, time-consuming, cumbersome to operate, easily mixed with impurities, and have low yield

miR-146a [20]; micoRNA-21 [73];

MiR-181b-5p [21];

GDNF、FGF-1、BDNF、IGF-1、NGF [22]

ATE

1. The lipoaspirate is left in ice water and discard the liquid portion

2. Then, the collected adipose tissue layer is washed with PBS

3. To remove remaining blood cells and other components, the adipose tissue is centrifuged at 1200 g for 3 min

4. The collected adipose tissue is mechanically emulsified

5. Then centrifuge at 2000 g for 5 min and filter with a 0.22-μm syringe filter

6. Or after being frozen and thawed for one cycle and centrifuge at 1200 g for 5 min, then filter with a 0.22-μm syringe filter

Rich in cytokines, but the source is relatively limited

VEGF [23,24,25,26] bFGF [24,25,26,27]

BDNF [23, 27];GDNF [23, 27] TGF-β [23, 26, 27];

HGF [23, 26, 27];

PDGF [23, 26, 27]; IGF-1 [80, 85];

KGF [28]