Improvement of the retention volume of fat transplantation by adipose tissue mesenchymal stem cell-derived microvesicles

Abstract

Objective To investigate the possibility of adipose tissue mesenchymal stem cell-derived microvesicles (ADSC-MVs) to improve the retention volume of fat transplantation. Methods Human adipose tissue was obtained from 5 healthy female patients aged from 20 to 30 years, who came to the hospital for abdominal liposuction. Adipose tissue mesenchymal stem cells (ADSCs) were acquired by collagenase enzymatic hydrolysis. ADSC-MVs were isolated from the supernatant of cultured ADSCs through ultra-centrifugation, and characterized by transmission electron microscope and PKH26 staining. Sixteen BALB/c-nu nude mice were randomly divided into 2 groups (n=8, mice/group) by random number table method. In EV group, the mice were subcutaneously injected 0.35 ml human fat, with 7 μg ADSC-EVs (final concentration is 20 μg/ml), while 0.35 ml human fat were in blank group. The mice were sacrificed and the grafts were harvested at 1 month and 3 months after transplantation. Weight and volume of transplanted fat were tested. Morphology of adipocytes, fibrosis and necrosis of fat tissue were confirmed by HE staining. Blood vessel density were accessed by CD31 staining.SPSS 13.0 was used for statistical analysis and Student-t test was applied to compare the data from two groups. Results One month after fat transplantation, the volume of fat grafts in blank group was lower than that in MV group. Besides, lipoliquefaction can be observed in fat grafts of blank group. Fat grafts in MV group had a higher volume and littler necrosis and lipolique faction. Three months after grafting, the volume of fat grafts in blank group [(0.057±0.009) ml] was significantly lower than that in MV group [(0.103±0.015) ml], t=8.117, P<0.001. MV group had an increased number of vessels (29.6±4.0/field) compared with grafts from the Blank group (23.0±2.4/field), t=2.825, P=0.022. Histological analysis revealed that the fat grafts in MV group consisted less fat necrosis and fibrosis than control group. Conclusions ADSC-MVs can improve the retention volume of fat transplantation. Key words: Adipose derived mesenchymal stem cells; Fat granule grafting; Microvesicles; Volume; Weight