Fig. 1From: The combination of stem cells and tissue engineering: an advanced strategy for blood vessels regeneration and vascular disease treatmentDownstream and upstream approaches to tissue engineering. In the downstream approach, multiple methods are used for creating modular tissues, which are then assembled into engineered tissues with specific micro-architectural features. In the upstream approach, cells and biomaterial scaffolds are combined and cultured until the cells fill the support structure to create an engineered tissueBack to article page