Adipose precursor cells (preadipocytes) induce formation of new vessels in fibrin glue on the newly developed cylinder chorioallantoic membrane model (CAM)

Successful augmentation of soft tissues by transplantation of preadipocytes within a matrix requires the formation of a new capillary network with connection to the host vessel system. Particularly, cells located centrally within the transplanted cell-matrix-construct represent a population with a blood supply questionable for survival. We demonstrated that under in vivo conditions preadipocytes possess the ability to induce and support the vascularization of the implant presumably by expression of several growth factors, such as VEGF ( vascular endothelial growth factor) and bFGF ( basic fibroblast growth factor). Fertilized White-Leghorn eggs were incubated under standardized conditions. Opening was performed at day three of incubation and preadipocytes with and without recombinant growth factors were transferred into a fibrin matrix and subsequently placed on the Chorioallantoic Membrane ( CAM), respectively. Eight days later, the implanted constructs were explanted, histologically processed and vascularization evaluated by means of a computer-assisted image analysis program. Matrices containing preadipocytes displayed a significantly higher density of vascularization, whereas in the control group ( fibrin without preadipocytes) no vessel ingrowth was observed. Daily application of recombinant growth factors added to the medium did not positively influence vascularization of the implant. Our investigations demonstrate that preadipocytes possess a strong angiogenic potential to induce and support neovascularization of 3D-fibrin matrices under in vivo conditions. Addition of recombinant growth factors did not result in any stimulatory effect. Neither did the application of fibrin alone demonstrate an angiogenic potential with regard to induction of vascularization.