Methods of screening for compounds that modulate blood vessel formation from circulating endothelial cell precursors

A method of screening for an agent that promotes vasculogenesis, comprising the steps of

• (a) co-culturing extraembryonic mesodermal stem cells and intraembryonic mesodermal stem cells, under conditions that allow formation of one or more vascular networks;
• (b) contacting the co-culture with the agent to be screened;
• (c) detecting, in one or more vascular networks, endothelial cells or endothelial cell precursors derived from extraembryonic mesodermal stem cells, or derivatives thereof;
• and
• (d) comparing the endothelial cells or endothelial cell precursors derived from extraembryonic mesodermal stem cells, or derivatives thereof, in the vascular network or networks in the culture contacted with the agent to be screened, with the endothelial cells or endothelial cell precursors derived from extraembryonic mesodermal stem cells, or derivatives thereof, in the vascular network or networks of the untreated cultures,
• an increase in endothelial cells or endothelial cell precursors derived from extraembryonic mesodennal stem cells, or derivatives thereof, in the vascular networks in the culture contacted with the agent to be screened indicating an agent that promotes vasculogenesis.

A method of screening for an agent that inhibits vasculogenesis, comprising the steps of

• (a) contacting one or more embryonic vascular networks with the agent to be screened, under conditions in which extraembryonic mesodermal stem cells, or derivatives thereof, can migrate to the embryonic vascular network or networks;
• (b) detecting, in the vascular network or networks, endothelial cells or endothelial cell precursors derived from extraembryonic mesodermal stem cells, or derivatives thereof, and
• (c) comparing the endothelial cells or endothelial cell precursors derived from extraembryonic mesodermal stem cells, or derivatives thereof, in the networks contacted with the agent to be screened, with the endothelial cells or endothelial cell precursors derived from extraembryonic mesodermal stem cells, or derivatives thereof, in untreated networks,
• an decrease in endothelial cells or endothelial cell precursors derived from extraembryonic mesodermal stem cells, or derivatives thereof, in the network or networks contacted with the agent to be screened indicating an agent that inhibits vasculogenesis.

A method of screening for an agent that inhibits vasculogenesis, comprising the steps of

• (a) co-culturing extraembryonic mesodermal stem cells and intraembryonic mesodermal stem cells, under conditions that allow formation of vascular networks;
• (b) contacting the co-culture with the agent to be screened;
• (c) detecting, in vascular networks, endothelial cells or endothelial cell precursors derived from extraembryonic mesodermal stem cells, or derivatives thereof;
• and
• (d) comparing the endothelial cells or endothelial cell precursors derived from extraembryonic mesodermal stem cells, or derivatives thereof, in the vascular networks in the culture contacted with the agent to be screened, with the endothelial cells or endothelial cell precursors derived from extraembryonic mesodermal stem cells, or derivatives thereof, in the vascular networks of the untreated cultures,
• an decrease in endothelial cells or endothelial cell precursors derived from extraembryonic mesodermal stem cells, or derivatives thereof, in the vascular networks in the culture contacted with the agent to be screened indicating an agent that inhibits vasculogenesis.