Migrating fetal astrocytes do not intravasate since they are excluded from blood vessels by vital basement membrane

Astrocytes appear to be excluded from blood vessels. In order to test this observation, pial blood vessels were seeded upon cultures of purified E14 fetal astrocytes. One to seven days later cocultures were immunohistochemically stained for laminin and fibronectin. Confocal microscopy revealed that laminin-positive cultured astrocytes migrated from the coverslip to and on to the surface of the blood vessels. The fetal astrocytes migrated along the basement membrane but did not enter the blood vessel. Viable (live) basement membrane is a barrier to astrocyte intravasation and is a pathway for astrocyte migration. Published by Elsevier Science Ltd.