Adipose-derived mesenchymal stem/stromal cells (ASCs) are an adult stem cell population able to self-renew and differentiate into numerous cell lineages. ASCs provide a promising future for therapeutic angiogenesis due to their ability to promote blood vessel formation. Specifically, their ability to differentiate into endothelial cells (ECs) and pericyte-like cells and to secrete angiogenesis-promoting growth factors and extracellular vesicles (EVs) makes them an ideal option in cell therapy and in regenerative medicine in conditions including tissue ischemia. In recent angiogenesis research, ASCs have often been co-cultured with an endothelial cell (EC) type in order to form mature vessel-like networks in specific culture conditions. In this review, we introduce co-culture systems and co-transplantation studies between ASCs and ECs. In co-cultures, the cells communicate via direct cell–cell contact or via paracrine signaling. Most often, ASCs are found in the perivascular niche lining the vessels, where they stabilize the vascular structures and express common pericyte surface proteins. In co-cultures, ASCs modulate endothelial cells and induce angiogenesis by promoting tube formation, partly via secretion of EVs. In vivo co-transplantation of ASCs and ECs showed improved formation of functional vessels over a single cell type transplantation. Adipose tissue as a cell source for both mesenchymal stem cells and ECs for co-transplantation serves as a prominent option for therapeutic angiogenesis and blood perfusion in vivo.

Adipose-derived mesenchymal stromal cells (ASCs) hold great potential for cellular therapies by having immunomodulatory behavior and tissue regenerative properties. Due to the capability of ASCs to differentiate into endothelial cells (ECs) and other angiogenic cell types, such as pericytes, ASCs are a highly valuable source for stimulating angiogenesis. However, cellular therapies in tissue engineering have faced challenges in poor survival of the cells after transplantation, which is why a protective biomaterial scaffold is required. In this work, we studied the potential of nanofibrillated cellulose (NFC) hydrogel to be utilized as a suitable matrix for three-dimensional (3D) cell culturing of human-derived ASCs (hASCs) and studied their angiogenic properties and differentiation potential in ECs and pericytes. In addition, we tested the effect of hASC-conditioned medium and stimulation with angiopoietin-1 (Ang-1) on human umbilical vein endothelial cells (HUVECs) to induce blood vessel-type tube formation in NFC hydrogel. The hASCs were successfully 3D cell cultured in NFC hydrogel as they formed spheroids and had high cell viability with angiogenic features. Most importantly, they showed angiogenic potential by having pericyte-like characteristics when differentiated in EC medium, and their conditioned medium improved HUVEC viability and tube formation, which recalls the active paracrine properties. This study recommends NFC hydrogel for future use as an animal-free biomaterial scaffold for hASCs in therapeutic angiogenesis and other cell therapy purposes.