Gene expression profiling of human stent-induced neointima by cDNA array analysis of microscopic specimens retrieved by helix cutter atherectomy - Detection of FK506-binding protein 12 upregulation

Background-Restenosis due to neointima formation is the major limitation of stent-supported balloon angioplasty. Despite abundant animal data, molecul ar mechanisms of neointima formation have been investigated on only a limit ed basis in patients. This study sought to establish a method for profiling gene expression in human in-stent neointima and to identify differentially expressed genes that may serve as novel therapeutic targets. Methods and Results We retrieved tissue specimens from patients with sympto matic in-stent restenosis using a novel helix cutter atherectomy device. cD NA samples prepared from neointima (n=10) and, as a control, from the media of normal arteries (n=14) were amplified using a novel polymerase chain re action protocol and hybridized to cDNA arrays. Immunohistochemistry charact erized the atherectomy material as neointima, cDNA arrays readily identifie d differentially expressed genes. Some of the differentially expressed gene s complied with expected gene expression patterns of neointima, including d ownregulation of desmin and upregulation of thrombospondin-l, cyclooxygenas e-l, and the 70-kDa heat shock protein B, Additionally, we discovered previ ously unknown gene expression patterns, such as downregulation of mammary-d erived growth inhibitor and upregulation of FK506-binding protein 12 (FKBP1 2), Upregulation of FKBP12 was confirmed at the protein level in neointimal smooth muscle cells. Conclusions-Gene expression patterns of human neointima retrieved by helix- cutter atherectomy can be reliably analyzed by cDNA array technology. This technique can identify therapeutic targets in patients, as exemplified by t he findings regarding FKBP12, FKBP12 is the receptor for Rapamycin (sirolim us), which in animal models reduced neointima formation. Our study thus yie lds a rationale for the use of Rapamycin to prevent restenosis in patients.