Cultrex RGF Basement Membrane Extract

The Tube Formation Assay is based on the ability of endothelial cells to form three-dimensional capillary-like tubular structures when cultured on a hydrogel of reconstituted basement membrane, such as Cultrex Basement Membrane Extract (BME).

The Tube Formation Assay is specific for endothelial cells, either primary cells or immortalized cell lines. Only endothelial cells form capillary-like structures with a lumen inside. Other endothelial cell types form other structures.

The major variables associated with tube formation are composition of the Cultrex Basement Membrane Extract (BME) hydrogel, thickness of the hydrogel, cell density, composition of angiogenic factors in the assay medium, and assay period.

The Tube Formation Assay is the most widely used in vitro angiogenesis assay. The assay is rapid, inexpensive and quantifiable. It can be used to identify potentially angiogenic and anti-angiogenic factors, to determine endothelial cell phenotype, and to study pathways and mechanisms involved in angiogenesis. It can be performed in a high throughput mode to screen for a large number of compounds.

Primary endothelial cells, such as Human Umbilical Vein Endothelial Cells (HUVECs) form capillary-like structures in the absence of added angiogenic factors less often than immortalized endothelial cells. Generally, reducing the number of cells per cm² plated onto Cultrex BME will result in less background or spontaneous tube formation. Titrate the number of cells and find optimal conditions for your specific cell line. When endothelial cells fully form capillary structures in response to angiogenic activators, but not in their absence, you may proceed.

All epithelial and endothelial cells are in contact with a basement membrane matrix on at least one of their surfaces. By providing them with their natural matrix in vitro as a substrate for the cells that provides biological cues, the cells can assume a more physiological morphology (i.e. correct shape) and begin expression of cell-lineage specific proteins. Two-dimensional plastic surfaces, in combination with serum-containing media, cause cells to flatten, proliferate and de-differentiate.

Cultrex Reduced Growth Factor BME (RGF BME) is generally used for testing compounds that promote angiogenesis because formation of capillary-like structures (tubes) is significantly less compared to non-growth factor reduced varieties of Cultrex BME. The Cultrex In Vitro Angiogeneis Assay (Tube Formation) includes a qualified production lot of Cultrex RGF BME that exhibits reduced background tube formation in the absence of angiogenic factors.