The objective of this project is to characterize the synthesis of the elastic component of the arterial vessel wall. The proposal is divided into four parts. The first goal is to determine whether cultured endothelial cells synthesize elastins or components of elastin and if so, to compare this elastin with that synthesized by vascular smooth cells in culture. Bovine aortic smooth muscle cells and endothelial cells, human umbilical cord smooth muscle cells, and endothelial cells will be studied. The second goal is to identify factors which may modulate the synthesis of elastin by human smooth muscle cells. Hormones, extracellular substratum and platelet factors will be studied as modulators. The last two goals are directed toward elaborating methods to identify and quantify elastin derived peptides in the serum of patients who have various vascular diseases and further to determine whether antibodies to elastin or elastin peptides are found in the serum of patients with vascular diseases. Three of these aims will make use of the ELISA assay for elastin developed in this laboratory.