In situ detection of platelet-derived growth factor-A and -B chain mRNA in human coronary arteries after percutaneous transluminal coronary angioplasty.

Experimental studies have shown that platelet-derived growth factor (PDGF) plays a role in wound-healing processes after angioplasty. In humans, after percutaneous transluminal coronary angioplasty (PTCA), this has not yet been documented. Six coronary arteries of five patients who died after PTCA were studied. The angioplasty sites were sliced serially, and the slices were studied using immunocytochemistry and in situ hybridization. Monoclonal antibodies were directed against muscle actin, vimentin, macrophages, and endothelium. In situ hybridization was performed using a synthetic oligonucleotide probe complementary to the 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 PTCA injury and related to areas that contained macrophages, spindle cells, smooth muscle cells, and endothelial cells of neovascularization. In humans, both PDGF-A and -B chain mRNAs are expressed at sites of PTCA injury. The expression relates to the reparative response, and it appears 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 sites of repair in human coronary arteries after PTCA. It suggests strongly that PDGF is involved in the repair process after PTCA.