The effect of hyaluronan hydrogel on fat graft survival

Autologous fat transplantation is a common technique for soft tissue augmentation in aesthetic and reconstructive surgery; however, the degree of fat graft take can be unpredictable. Hyaluronan has been shown to be a promising cell carrier in adipose tissue engineering.

The authors investigate the effect of a hyaluronan hydrogel on fat graft survival, angiogenesis, and volume maintenance in a rat model.

Fat was harvested from the groins of 27 rats, processed, and injected beneath the animals' dorsums to form 2 grafts: 1 containing fat alone and 1 containing fat and hyaluronan hydrogel in a 1:1 mix (fat-HA). The grafts were scanned in vivo under high-resolution computed tomography at baseline and prior to euthanasia at 4, 12, and 20 weeks to measure total fat-HA graft volume as well as the volume of the fat component alone. Histological studies were performed after sacrifice to evaluate fat necrosis and blood vessel density.

All grafts were clinically viable. Overall, fat necrosis was significantly reduced in the fat-HA grafts compared with the grafts containing fat alone (P < .001). This difference was most profound at 4 weeks (P = .008) but did not reach statistical significance at 12 and 20 weeks. At 12 weeks, blood vessel density in the fat-HA grafts was significantly greater than in the grafts containing fat alone (P = .016), but this did not reach statistical significance at 4 or 20 weeks. At 20 weeks, the fat component of the fat-HA graft had significantly less volume loss than the fat-alone graft (P = .008).

When mixed with fat, hyaluronan hydrogel can improve early fat graft survival and may enhance vascularity and prolong volume maintenance.