Due to its availability and minimal invasive harvesting human adipose tissue-derived extracellular matrix (dECM) is often used as a biomaterial in various tissue engineering and healthcare applications. Next to dECM, cell-derived ECM (cdECM) can be generated by and isolated from in vitro cultured cells. So far both types of ECM were investigated extensively towards their application as (bio)material in tissue engineering and healthcare. However, a systematic characterization and comparison of soft tissue dECM and cdECM is still missing. In this study, we characterized dECM from human adipose tissue, as well as cdECM from human adipose-derived stem cells (ASCs), towards their molecular composition, structural characteristics, and biological purity. The dECM was found to exhibit higher levels of collagens and lower levels of sulfated glycosaminoglycans (sGAGs) compared to cdECMs. Structural characteristics revealed an immature state of the fibrous part of cdECM samples. By the identified differences, we aim to support researchers in the selection of a suitable ECM-based biomaterial for their specific application and the interpretation of obtained results.

Tissue constructs of physiologically relevant scale require a vascular system to maintain cell viability. However, in vitro vascularization of engineered tissues is still a major challenge. Successful approaches are based on a feeder layer (FL) to support vascularization. Here, we investigated whether the supporting effect on the self-assembled formation of vascular-like structures by microvascular endothelial cells (mvECs) originates from the FL itself or from its extracellular matrix (ECM). Therefore, we compared the influence of ECM, either derived from adipose-derived stem cells (ASCs) or adipogenic differentiated ASCs, with the classical approaches based on a cellular FL. All cell-derived ECM (cdECM) substrates enable mvEC growth with high viability. Vascular-like structure formation was visualized by immunofluorescence staining of endothelial surface protein CD 31 and can be observed on all cdECM and FL substrates but not on control substrate collagen I. On adipogenic differentiated ECM longer and higher branched structures can be found compared to stem cell cdECM. An increased concentration of pro-angiogenic factors can be found in cdECM substrates and FL approaches compared to controls. Finally, expression of proteins associated with tube formation (E-selectin and thrombomodulin) was confirmed. These results highlight cdECM as promising biomaterial for in vitro vascularization in adipose tissue engineering.