Microsurgical arterovenous loops and biological templates: a novel in vivo chamber for tissue engineering.

Microsurgical tissue engineering is an emerging topic in regenerative medicine. Here we describe a new microsurgical model of bioengineering in rats based on the use of an arterovenous loop (AV) implanted into a commercially available crosslinked collagen/glycosaminoglycan template.The microvascular loop was created between the femoral artery and vein and covered by the template folded onto itself. The chamber was isolated from the outside tissue by an outer silicon layer to impede tissue ingrowth.At 1-month postimplantation, the tissue chamber was found heavily vascularized, as assessed by laser Doppler perfusion analysis. Histological examination showed that the AV loop was integrated into the collagen matrix of the template and that the whole template was filled with a newly formed soft connective tissue. Most interestingly, the whole scaffold was found heavily vascularized, including the formation of a large number of alpha-SMA-positive arterioles.The developed microsurgical chamber provides a highly vascular, isolated tool for in vivo tissue engineering.