The tissue-engineered breast

The adipose tissue engineering paradigm of in vitro cell-seeded scaffolds subsequently implanted in vivo failed because of inadequate vascularization. Consequently, entirely in vivo models of tissue engineering are being trialled where angiogenic growth is stimulated in unison with expansion of implanted cells and matrices. In animals, impressive amounts of fat and fibroblastic tissue have been grown by matrix induction of preadipocytes or by redirecting a vascular pedicle with fat into a sealed chamber space and proof of principle shown in a human trial. The models are cumbersome limiting clinical translation and currently direct fat transfer by injection is simpler. Unlike true tissue engineering there is, however, no net gain of tissue and even when ‘successful’ it is debated whether the graft survives or is replaced by newly regenerated adipocytes. Research focuses on stem cell differentiation, cell survival, and matrix and biomechanical manipulations.