Joris van Dongen

280 Chapter 12 ABSTRACT Introduction Fat grafting is an established clinical intervention to promote tissue repair. The role of the fat’s extracellularmatrix (ECM) in regeneration is largely neglected.We investigated in vitro the use of human adipose tissue-derived ECM hydrogels as release platform for factors secreted by adipose derived stromal cells (ASC). Material & methods Lipoaspirates from non-diabetic and diabetic donors were decellularized. Finely powdered acellular ECMwas evaluated for cell remainders and DNA content. Acellular ECMwas digested and hydrogels were formed at 37 °C and their viscoelastic relaxation properties investigated. Release of ASC-released factors from hydrogels was immune- assessed and bio-activitywas determined by fibroblast proliferation and migration and endothelial angiogenesis. Results Acellular ECM contained no detectable cell remainders and negligible DNA contents. Viscoelastic relaxation measurements yielded no data for diabetic-derived hydrogels due to gel instability. Hydrogels released several ASC-released factors concurrently in a sustained fashion. Functionally, released factors stimulated fibroblast proliferation and migration as well as angiogenesis. No difference between non-diabetic and diabetic hydrogels in release of factors was measured. Conclusion Adipose ECM hydrogels incubated with released factors by ASC are a promising new therapeutic modality to promote several important wound healing related processes by releasing factors in a controlled way.