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The success of many therapies in regenerative medicine requires the ability to control the formation of stable vascular networks within tissues. The formation of new blood vessels, or neovascularization, is mediated, in part, by interactions between endothelial cells (ECs) and insoluble factors in the extracellular microenvironment. These interactions are determined by the chemical, physical, and mechanical properties of the matrix. Understanding how extracellular matrices (ECMs) and synthetic scaffolds influence neovascularization can contribute to the fundamental knowledge of normal and diseased tissue physiology and can be used to guide the design of new therapies. The goal of this review is to provide an overview of the complex role EC-matrix interactions play in neovascularization. A particular emphasis is placed on presenting differences in two subsets of ECM, basement membranes and stromal matrices, and identification of the properties of these matrices that define their biological functions. Attempts to apply information about EC-ECM interactions to enhance vascularization of synthetic materials are presented, and areas in need of further research are identified throughout this review. Our understanding of the role EC-matrix interactions play in neovascularization remains limited, but continued progress in this area could be of significant benefit to the design of clinically applicable engineered tissues.

Abstract: Biomaterials that induce adipogenesis may ultimately serve as alternatives to traditional tissue reconstruction and regeneration techniques. In addition, these materials can provide environments for studying factors that regulate adipogenesis. The present study investigates the potential of adipose-derived matrices to induce adipogenesis in vitro and in vivo. Solutions containing basement membrane proteins and growth factors were extracted from subcutaneous adipose tissue. These extracts could be induced to form gels by either incubating the solutions at 37°C or adjusting the pH to 4.0. The adipose extracts promoted rapid preadipocyte aggregation and formation of lipid-loaded colonies in vitro. Differentiation on adipose-derived gels was greater than tissue culture dishes and the tumor-derived product Matrigel™ (p <0.05). Significant adipose formation was observed when adipose-derived gels were implanted around a rat epigastric pedicle bundle. Adipose levels in these gels were significantly greater than Matrigel™ (p <0.05). The duration of adipose formation depended on the mechanism for gelling the solutions, with acid gelled matrices having greater adipose levels at 6 weeks than temperature gelled matrices. These adipose-derived hydrogels promote rapid adipogenesis in vitro and in vivo. They may lead to new materials for adipose tissue engineering, and provide an environment for studying cell–matrix interactions in adipogenesis. [Copyright &y& Elsevier]