Revascularization of transplanted adipose tissue: A study in the dorsal skinfold chamber of hamsters

Adipose tissue seems to be an ideal material for use as a permanent soft-tissue substitute in reconstructive surgery. However, knowledge of the behavior of the graft - in particular, its revascularization - is scarce. Therefore, the aim of the current study was to establish a novel model that allows for long-term in vivo quantitative analysis of revascularization of adipose tissue after transplantation. Hamsters (n = 8) were fitted with transparent titanium dorsal skinfold chambers. Immediately after en bloc harvest of adipose tissue from the left inguinal area, the graft was placed gently into the chamber. At days 1, 3, 12, and 21, red blood cell-perfused vessels were assessed in surrounding host tissue, in the border of the graft, and in its center (n = 6 areas each) using intravital fluorescent microscopy. The model allowed for permanent observations of adipose tissue and quantitative analysis of functional vessel density (FVD). At the border zone of the graft, an FVD of 2 ± 1 cm per cm² was measured at day 1. In this region FVD increased constantly and finally reached values (184 ± 10 cm per cm²; day 21) that were comparable with those of the surrounding host tissue. Revascularization in the center of the graft started at day 3 after transplantation (14 ± 3 cm per cm²). Here, FVD increased constantly, but lower values compared with the grafts' border zone were measured (139 ± 10 cm per cm²; day 21). FVD data obtained from transplanted adipose tissue may contribute to understanding fundamental mechanisms of graft failure.