THE IMPORTANCE OF THROMBUS ORGANIZATION AND STELLATE CELL PHENOTYPE IN COLLAGEN-I GENE-EXPRESSION IN HUMAN, CORONARY ATHEROSCLEROTIC AND RESTENOTIC LESIONS

Objectives:: Collagen synthesis is one of the major mechanisms of prim ary atherosclerotic plaque growth and is likely to be similarly import ant in restenosis. The patterns of collagen gene expression in human r estenosis and associations with thrombosis/hemorrhage have not been de scribed. Methods: Using human coronary artery samples obtained via the atherectomy catheter, we compared primary plaques (40 specimens) and restenotic lesions (41 specimens) for type I collagen gene expression using immunocytochemistry (SPI.D8 antibody to type I procollagen, an i ntracellular precursor of mature collagen) with subsequent computer im age analysis, Results: Scattered positive cells were identified in spe cific, non-random patterns. According to logistic regression analyses, type I procollagen gene expression seems to be more closely associate d with certain morphological features (organized thrombus, microvessel s, regions enriched with stellate cells) than with belonging to a prim ary vs. a restenotic sample. However, there may be a tendency for rest enotic tissue to have slightly higher numbers of type I procollagen-po sitive cells than primary lesion tissue. Conclusions: Symptomatic prim ary and restenotic lesions exhibit similar patterns of type I collagen gene expression. Plaque microvessels and thrombi/hemorrhages (common features of both kinds of advanced lesions) might stimulate collagen s ynthesis equally well irrelevant to the nature of the lesion.