IN-SITU DETECTION OF PLATELET-DERIVED GROWTH FACTOR-A AND FACTOR-B CHAIN MESSENGER-RNA IN HUMAN CORONARY-ARTERIES AFTER PERCUTANEOUS TRANSLUMINAL CORONARY ANGIOPLASTY

Experimental studies have shown that platelet-derived growth factor (P DGF) plays a role in wound-healing processes after angioplasty. In hum ans, after percutaneous transluminal coronary angioplasty (PTCA), this has not yet been documented. Six coronary arteries of five patients w ho died after PTCA were studied. The angioplasty sites were sliced ser ially, and the slices were studied using immunocytochemistry and in si tu hybridization. Monoclonal antibodies were directed against muscle a ctin, vimentin, macrophages, and endothelium. In situ hybridization wa s performed using a synthetic oligonucleotide probe complementary to t he PDGF-A and -B chain mRNAs. The identification of cells was based on a comparison with immune-stained sections. Positive autoradiographic signals for PDGF-A and -B chain mRNAs were found at the site of the PT CA injury and related to areas that contained macrophages, spindle cel ls, smooth muscle cells, and endothelial cells of neovascularization. In humans, both PDGF-A and -B chain mRNAs are expressed at sites of PT CA injury. The expression relates to the reparative response, and it a ppears that the cells involved are macrophages, spindle cells, smooth muscle cells, and endothelial cells of neovascularization. This is the first study to document the expression of PDGF-A and -B mRNAs at site s of repair in human coronary arteries after PTCA. It suggests strongl y that PDGF is involved in the repair process after PTCA.