Foreword

A frequently used approach to understanding the mechanisms and fundamental processes involved in vessel formation is to study the processes that occur in the development of a fetus. This technique has been used for more than a century, and the first manuscript by Karen Downs reviews some of the pivotal early developmental studies by Francis Sabin, which provided the first insights into the mechanisms of lumen formation. It is clear Sabin’s strongly supported observations on vacuolation have been overlooked in modern times as any careful survey of the plethora of review articles that have been written on angiogenesis over the last decade will reveal. The subject of vessel lumina formation is either overlooked altogether or has been suggested to be due to the formation of filopodial connections, in the absence of any supportive data. Dr. Downs suggests that the mouse allantois, composed wholly of mesoderm and dedicated to the formation of a vascular system, might be a new and exciting substratum in which to address the means of blood vessel lumina formation. Use of the mouse allantois offers the opportunity to exploit the numerous mouse mutants to discover the genetic pathways leading to the formation of vascular lumens.