NEURAL CREST CELL CONTRIBUTION TO THE DEVELOPING CIRCULATORY-SYSTEM -IMPLICATIONS FOR VASCULAR MORPHOLOGY

In this study, the distribution patterns of neural crest (NC) cells (N CCs) in tile developing vascular system of the chick were thoroughly s tudied and examined for a correlation with smooth muscle cell differen tiation and vascular morphogenesis. For this purpose, we performed lon g-term lineage tracing using quail-chick chimera techniques and premig ratory NCC infection with a replication-incompetent retrovirus contain ing the LacZ reporter gene in combination with immunohistochemistry. R esults indicate that NCC deposition around endothelial tubes is influe nced by anteroposterior positional information from the pharyngeal art erial system, NCCs were shown to be among the first cells to different iate into primary smooth muscle cells of the arch arteries, At later s tages, NCCs eventually differentiated into adventitial fibroblasts and smooth muscle cells and nonmuscular cells of the media and intima. NC Cs were distributed in the aortic arch and pulmonary arch arteries and in the brachiocephalic and carotid arteries. The coronary and pulmona ry arteries and the descending aorta, however, remained devoid of NCCs . A new finding was that the media of part of the anterior-cardinal ve ins was also determined to be NC-derived. NC-derived elastic arteries differed from non-NC elastic vessels in their cellular constitution an d elastic fiber organization, and the NC appeared not to be involved i n designating a muscular or elastic artery. Boundaries between NC-infe sted areas and mesodermal vessel structures were mostly very sharp and tended to coincide with marked changes in vascular morphology, with t he exception of an intriguing area in the aortic and pulmonary trunks.