Activated macrophages as key mediators of capsule formation on adipose constructs in tissue engineering chamber models.

In plastic and reconstructive field, it would be much beneficial to fabricate an engineered adipose tissue substitute allowing reliable and complete fat tissue regeneration. Tissue engineering chamber (TEC) holds the promise to optimize an adipogenic configuration that is efficacious as well as reproducible. A frequently occurring complication involves the adipose tissue flap encapsulation and, effectively, its shielding, by a thick fibrous membrane, which hinders development into the proliferative stage. The reason for the deposition of the collagen capsule remains unclear. Numerous studies have highlighted that macrophages play a key role in adipogenesis in a TEC model using a silicone chamber enclosing the fat flap with a superficial epigastric pedicle. As a verification of the role of macrophages in capsule formation, we propose the inhibition of transforming growth factor β1 (TGF-β1) synthesis by macrophage populations in the local microenvironment by administrating tranilast into the TEC. We hypothesize that upon reduction of TGF-β1 levels, capsule formation and inhibition of new adipose tissue development will decrease. Furthermore, we propose that a tissue engineering chamber model in which macrophages are closely related to both neo-adipogenesis and capsule formation.